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in a decreased twinning propensity in species such as giraffes, elephants, and hippopotami. Despite this adaptation, a case of rare monozygotic twinning has been documented in two elephant calves at the
Bandipur Tiger Reserve in Karnataka, India. Chief Veterinarian of the Wildlife Trust of India, NVK Ashraf, in response to the twinning event, wrote that "in species that invest longer time in producing a baby, taking care of two twin calves will be difficult. Therefore, the incidence of twinning will be comparatively less."Ashraf's insight not only illuminates the rarity of twinning among large mammals in the natural world, but directs our attention to the increased twinning propensity of animals under human care. This increased twinning propensity is thought to be either caused by random mutation facilitated by genetic drift, or the positive selection of the "twinning" trait in human-controlled conditions. Due to the removal of natural predators and unpredictable environmental conditions with the increase of human-provided food and medical care, species residing in nature reserves, zoos, etc., carry an increased likelihood of reversing their naturally-selected traits that have been passed on for generations. When considering this phenomenon in relation to twinning, larger mammals not commonly associated with high twinning propensities can perhaps produce twins as an adaptive response to their human-controlled environment. Additionally, the high twinning propensity in species is thought to be positively correlated with the infant mortality rate of the reproducing organism's environment (Rickard, 2022, p.2). Thus if a species lives in a controlled environment with a low infant mortality rate, the frequency of the "twinning trait" could increase, leading to a higher likelihood of producing twin offspring. In the case of the monozygotic twin calves in India, their existence could be connected to a new, positively selected adaptation of twinning attributed to species living under human care (Ward, 2014, p.7-11).
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produce twins because of their small size and insect-based diet (Varella, 2018). This is because their small size indicates shorter gestation periods and the rapid maturation of offspring, resulting in a shorter lifespan where organisms are rapidly replaced by newer generations. The smaller size of the cebidae genus also makes these species more susceptible to predators, thus triggering the heightened pace of birth, maturation, reproduction, and death. Meanwhile, cebidae's insectivorous existence can be correlated with this genus's heightened ability to reproduce, as more resources become available, more organisms can take advantage of these resources. Thus, monkeys that are smaller and have more access to food, such as the cebidae genus, have the ability to produce more offspring at a quicker pace. In terms of dizygotic twinning, it has been observed that older mothers within the cebidae genus have a higher chance of producing twins than those at the beginning stages of their fertility. Despite their access to resources, the cebidae genus has a high mortality rate attributed to their size, meaning that in order to "keep up" their quickened lifecycle, they must produce an excess of offspring in ensuring generational survival. The positively-selected adaptation of twinning counteracts the genus's high mortality rate by giving older mothers the chance to produce more than one offspring. This not only increases the likelihood that one or more of these offspring will reach reproductive maturity, but gives the mother a chance to birth at least one viable offspring despite their age. Due to their short life cycles, the cebidae genus is more inclined to produce dizygotic twins in their older reproductive years, thus signaling that the trait of high twinning propensity is one that is passed down in service of this genus's survival.
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higher twinning propensities. In his study on the evolution of litter size in bats, Garbino discovered that the vespertilionidae genus has higher twinning propensities as a result of their high roosting habitats. When tracked phylogenetically, scientists determined that the common ancestor of bats carried a higher twinning propensity which was then lost, and picked up again, eighteen times in evolutionary history. While other bat subfamilies such as
Myotinae and Murinae inevitably lost the twinning trait, the family Vespertilionidae retained a high trait frequency due to mutation and environmental conditions that triggered natural selection. The height and exposed nature of Vespertilionidae's roosting locations resulted in a sharp increase in species mortality rate. Natural selection offsets these dangers by positively selecting high twinning propensity, resulting in not only Vespertilionidae's increased ability to produce twins but the increased likelihood of the genus's reproductive survival. This means that despite the family's high exposure to factors that would seemingly increase mortality rates, Vespertilionidae counteracts their environmental conditions through the evolutionary adaptation of dizygotic twins.
812:
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1276:. There is controversy on the best method of delivery where the first twin is head first and the second is not. When the first twin is not head down a caesarean section is often recommended. It is estimated that 75% of twin pregnancies in the United States were delivered by caesarean section in 2008. In comparison, the rate of caesarean section for all pregnancies in the general population varies between 14% and 40%. In twins that share the same placenta, delivery may be considered at 36 weeks. For twins who are born early, there is insufficient evidence for or against placing preterm stable twins in the same cot or incubator (co-bedding).
1599:" (Horton, 2016). Additionally, armadillos have also been known to produce monozygotic twins, sometimes birthing two sets of identical twins during one reproductive cycle. Monozygotic twinning in armadillos functions as an evolutionary adaptation preventing inbreeding. Once an armadillo offspring enters its reproductive stage, the organism is forced to leave the nest in search of its mate, rather than mating with its siblings. Not only does monozygotic twinning dissuade from armadillo siblings inbreeding, but by forcing migration from the nest, this adaptation ensures the increased
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398:
469:, caused by differing environmental influences throughout their lives. Epigenetics refers to the level of activity of any particular gene. A gene may become switched on, switched off, or could become partially switched on or off in an individual. This epigenetic modification is triggered by environmental events. Monozygotic twins can have markedly different epigenetic profiles. A study of 80 pairs of monozygotic twins ranging in age from three to 74 showed that the youngest twins have relatively few
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913:, there were 40 twins and 2 triplets per 1000 births. Twenty-six percent of twins were monozygotic. The incidence of multiple births, which was about five times higher than that observed in any western population, was significantly lower than that of other ethnic groups, who live in the hot and humid climate of the southern part of the country. The incidence of multiple births was related to maternal age but did not bear any association to the climate or prevalence of
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isolate them from the social environment surrounding them. Idioglossia has been found to be a rare occurrence and the attention of scientists has shifted away from this idea. However, there are researchers and scientists that say cryptophasia or idioglossia is not a rare phenomenon. Current research is looking into the impacts of a richer social environment for these twins to stimulate their development of language.
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718:
42:
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80:('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In very rare cases twins can have the same mother and different fathers (
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1449:. In their seminal publication, Gabbett, Fisk and colleagues documented a second case of sesquizygosis and presented molecular evidence of the phenomenon. The reported twins shared 100% of their maternal chromosomes and 78% of their paternal genomic information. The authors presented evidence that two
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In 2007, a study reported a case of a pair of living twins, which shared an identical set of maternal chromosomes, while each having a distinct set of paternal chromosomes, albeit from the same man, and thus they most likely share half of their father's genetic makeup. The twins were both found to be
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could be responsible for the high ratio of twins in the area. His theory was rejected by
Brazilian scientists who had studied twins living in Linha São Pedro; they suggested genetic factors within that community as a more likely explanation. A high twinning rate has also been observed in other places
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A chimera is an ordinary person or animal except that some of their parts actually came from their twin or from the mother. A chimera may arise either from monozygotic twin fetuses (where it would be impossible to detect), or from dizygotic fetuses, which can be identified by chromosomal comparisons
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Monozygotic twins are genetically nearly identical and they are the same chromosomal sex unless there has been a mutation during development. The children of monozygotic twins test genetically as half-siblings (or full siblings, if a pair of monozygotic twins reproduces with another pair or with the
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Due to the increased parental investment provided for their offspring, larger mammals with longer life spans have slower reproductive cycles and tend to birth only one offspring at a time. This commonly repeated behavior in larger mammals evolved as a fixed, naturally-selected adaptation, resulting
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is defined as a private language that is usually invented by young children, specifically twins. Another term to describe what some people call "twin talk" is cryptophasia where a language is developed by twins that only they can understand. The increased focused communication between two twins may
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Conjoined twins (or the once-commonly used term "siamese") are monozygotic twins whose bodies are joined during pregnancy. This occurs when the zygote starts to split after day 12 following fertilization and fails to separate completely. This condition occurs in about 1 in 50,000 human pregnancies.
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There were 836,104 deliveries of babies in Hesse over the 15-year study period, including 11,740 twin pregnancies, of which only 4,110 met the inclusion criteria and hence were examined in the study. The excluded twin pregnancies were in cases of (1) delivery before 34 weeks of gestation; (2) when
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species, scientists
Guilherme Siniciato Terra Garbino (2021) and Marco Varella (2018) have proven that smaller species experiencing infertility in old age and/or unstable habits as a result of increased predation or human interference can experience have undergone natural selection in gaining even
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occurs when a fetus dies after 20 weeks of gestation. There are two types of stillbirth, including intrauterine death and intrapartum death. Intrauterine death occurs when a baby dies during late pregnancy. Intrapartum death, which is more common, occurs when a baby dies while the mother is giving
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known to occur in human populations. Polymorphisms appeared in 2 of the 33 million comparisons, leading the researchers to extrapolate that the blood cells of monozygotic twins may have on the order of one DNA-sequence difference for every 12 million nucleotides, which would imply hundreds of
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The prevalence of dizygotic twinning in monkeys is thought to be an "insurance adaptation" for mothers reproducing at the end of their fertile years. While dizygotic twinning has been observed in species such as gorillas and chimpanzees, monkeys in the cebidae genus are found to be more likely to
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The study stated that the occurrence of complications "was found to be more likely with increasing twin-to-twin delivery time interval" and suggested that the interval be kept short, though it noted that the study did not examine causes of complications and did not control for factors such as the
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The likelihood of a single fertilization resulting in monozygotic twins is uniformly distributed in all populations around the world. This is in marked contrast to dizygotic twinning, which ranges from about six per thousand births in Japan (almost similar to the rate of identical twins, which is
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Jonsson, Hakon; Magnusdottir, Erna; Eggertsson, Hannes P.; Stefansson, Olafur A.; Arnadottir, Gudny A.; Eiriksson, Ogmundur; Zink, Florian; Helgason, Einar A.; Jonsdottir, Ingileif; Gylfason, Arnaldur; Jonasdottir, Adalbjorg; Jonasdottir, Aslaug; Beyter, Doruk; Steingrimsdottir, Thora; Norddahl,
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Among non-twin births, male singletons are slightly (about five percent) more common than female singletons. The rates for singletons vary slightly by country. For example, the sex ratio of birth in the US is 1.05 males/female, while it is 1.07 males/female in Italy. However, males are also more
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Among monozygotic twins, in extremely rare cases, twins have been born with different sexes (one male, one female). When monozygotic twins are born with different sexes it is because of chromosomal defects. The probability of this is so small that multiples having different sexes is universally
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The degree of separation of the twins in utero depends on if and when they split into two zygotes. Dizygotic twins were always two zygotes. Monozygotic twins split into two zygotes at some time very early in the pregnancy. The timing of this separation determines the chorionicity (the number of
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differences. The number of epigenetic differences increases with age. Fifty-year-old twins had over three times the epigenetic difference of three-year-old twins. Twins who had spent their lives apart (such as those adopted by two different sets of parents at birth) had the greatest difference.
163:. There is no known genetic link for identical twinning. Other factors that increase the odds of having fraternal twins include maternal age, fertility drugs and other fertility treatments, nutrition, and prior births. Some women intentionally turn to fertility drugs in order to conceive twins.
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A very rare type of parasitic twinning is one where a single viable twin is endangered when the other zygote becomes cancerous, or "molar". This means that the molar zygote's cellular division continues unchecked, resulting in a cancerous growth that overtakes the viable fetus. Typically, this
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Multiple pregnancies are much less likely to carry to full term than single births, with twin pregnancies lasting on average 37 weeks, three weeks less than full term. Women who have a family history of fraternal twins have a higher chance of producing fraternal twins themselves, as there is a
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Species with small physicalities and quick reproductive cycles carry high twinning propensities as a result of increased predation and high mortality rates. As scientists continue to study the origin of dizygotic twinning in the animal kingdom, many have turned to species that demonstrated an
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differences across the entire genome. The mutations producing the differences detected in this study would have occurred during embryonic cell-division (after the point of fertilization). If they occur early in fetal development, they will be present in a very large proportion of body cells.
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in the animal kingdom are rare but have been recorded on a number of occasions. In 2016, a C-section of an Irish
Wolfhound revealed identical twin puppies sharing a singular placenta. South African scientists, who were called in to study the identical twins wrote that... "To the best of our
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There have also been cases in which twins are born a number of days apart. Possibly the worldwide record for the duration of the time gap between the first and the second delivery was the birth of twins 97 days apart in
Cologne, Germany, the first of which was born on November 17, 2018.
1488:). If the split occurs later than this time period, the twins risk being conjoined. There is no DNA-based zygosity test that can determine if twins are indeed mirror image. The term "mirror image" is used because the twins, when facing each other, appear as matching reflections.
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suggesting that identical twins may not be quite as identical as previously thought. The four-year study of monozygotic (identical) twins and their extended families revealed that these twins have genetic differences that begin in the early stages of embryonic development.
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exams sometimes reveal an "extra" fetus, which fails to develop and instead disintegrates and vanishes in the uterus. There are several reasons for the "vanishing" fetus, including it being embodied or absorbed by the other fetus, placenta or the mother. This is known as
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Mirror image twins result when a fertilized egg splits later in the embryonic stage than normal timing, around day 9–12. This type of twinning could exhibit characteristics with reversed asymmetry, such as opposite dominant handedness, dental structure, or even organs
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in twins compared to single-born children. These studies have converged on the notion that there is a greater rate of delay in language development in twins compared to their single-born counterparts. The reasons for this phenomenon are still in question; however,
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birth. The cause of stillbirth is often unknown, but the rate of babies who are stillborn is higher in twins and multiple births. Caesareans or inductions are advised after 38 weeks of pregnancy for twins, because the risk of stillbirth increases after this time.
542:. Non-conjoined monozygotic twins form up to day 14 of embryonic development, but when twinning occurs after 14 days, the twins will likely be conjoined. Furthermore, there can be various degrees of shared environment of twins in the womb, potentially leading to
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Souter, Vivienne L; Parisi, Melissa A; Nyholt, Dale R; Kapur, Raj P; Henders, Anjali K; Opheim, Kent E; Gunther, Daniel F; Mitchell, Michael E; Glass, Ian A; Montgomery, Grant W (2007). "A case of true hermaphroditism reveals an unusual mechanism of twinning".
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twins can develop differently, due to their genes being differently activated. More unusual are "semi-identical twins", also known as "sesquizygotic". As of 2019, only two cases have been reported. These "half-identical twins" are hypothesized to occur when an
409:. In 18–30% of monozygotic twins each fetus has a separate placenta and a separate amniotic sac. A small number (1–2%) of monozygotic twins share the same placenta and amniotic sac. Fraternal twins each have their own placenta and own amniotic sac.
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Dizygotic twins are also more common for older mothers, with twinning rates doubling in mothers over the age of 35. With the advent of technologies and techniques to assist women in getting pregnant, the rate of fraternals has increased markedly.
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Another abnormality that can result in monozygotic twins of different sexes is if the egg is fertilized by a male sperm but during cell division only the X chromosome is duplicated. This results in one normal male (XY) and one female with
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Studies show that there is a genetic proclivity for dizygotic twinning. However, it is only the mother who has any effect on the chances of having such twins; there is no known mechanism for a father to cause the release of more than one
1194:. More than half of twins are born weighing less than 5.5 pounds (2.5 kg), while the average birth weight of a healthy baby should be around 6–8 pounds (3–4 kg). This is largely due to the fact that twins are typically born
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Researchers suspect that as many as 1 in 8 pregnancies start out as multiples, but only a single fetus is brought to full term, because the other fetus has died very early in the pregnancy and has not been detected or recorded. Early
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mothers (who exclude dairy from their diets) are one-fifth as likely to have twins as vegetarian or omnivore mothers, and concluded that "Genotypes favoring elevated IGF and diets including dairy products, especially in areas where
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cycle, identical to the ovulation of dizygotic twins, they produce more than two offspring. Species such as sheep, goats, and deer have a higher propensity for dizygotic twinning, meaning that they carry a higher frequency of the
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Bieber, Frederick R.; Walter E. Nance; Cynthia C. Morton; Judith A. Brown; Fay O. Redwine; Robert L. Jordan and T. Mohanakumar (1981-08-14). "Genetic
Studies of an Acardiac Monster: Evidence of Polar Body Twinning in Man".
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The vast majority of twins are either dizygotic (fraternal) or monozygotic (identical). In humans dizygotic twins occur more often than monozygotic twins. Less common variants are discussed further down the article.
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placentae) and amniocity (the number of sacs) of the pregnancy. Dichorionic twins either never divided (i.e.: were dizygotic) or they divided within the first 4 days. Monoamnionic twins divide after the first week.
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Monozygotic twins who share a placenta can develop twin-to-twin transfusion syndrome. This condition means that blood from one twin is being diverted into the other twin. One twin, the 'donor' twin, is small and
2098:"My father is an identical twin and my husband's grandfather is a fraternal twin. Does this increase our changes of having twins, or is the genetic trait only on the mother's side and only for fraternal twins?"
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Most conjoined twins are now evaluated for surgery to attempt to separate them into separate functional bodies. The degree of difficulty rises if a vital organ or structure is shared between twins, such as the
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Am J Med Genet C Semin Med Genet. 2009 May 15;151C(2):136-41. Not really identical: epigenetic differences in monozygotic twins and implications for twin studies in psychiatry. Haque FN, Gottesman II, Wong
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Non-human dizygotic twinning is a common phenomenon in multiple animal species, including cats, dogs, cattle, bats, chimpanzees, and deer. This should not be confused with an animal's ability to produce a
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Twin studies are utilized in an attempt to determine how much of a particular trait is attributable to either genetics or environmental influence. These studies compare monozygotic and dizygotic twins for
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Women undergoing certain fertility treatments may have a greater chance of dizygotic multiple births. In the United States it has been estimated that by 2011 36% of twin births resulted from conception by
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twin. The authors were unable to predict whether a healthy fetus could result from a polar body twinning. However, a study in 2012 found that it is possible for a polar body to result in a healthy fetus.
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Li R, Montpetit A, Rousseau M, Wu SY, Greenwood CM, Spector TD, Pollak M, Polychronakos C, Richards JB (January 2014). "Somatic point mutations occurring early in development: a monozygotic twin study".
1198:. Premature birth and low birth weights, especially when under 3.5 pounds (1.6 kg), can increase the risk of several health-related issues, such as vision and hearing loss, mental disabilities, and
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however, because even within the confines of the womb, the fetuses touch different parts of their environment, giving rise to small variations in their corresponding prints and thus making them unique.
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automatically implies dizygotic twins, but if monozygotic twins separate early enough, the arrangement of sacs and placentas in utero is in fact indistinguishable from that of dizygotic twins.
675:. Also, the two umbilical cords have an increased chance of being tangled around the babies. Because of this, there is an increased chance that the newborns may be miscarried or suffer from
2055:
Unlike singleton gestation where identification of patients at risk for PTL is often difficult, every multiple gestation is at risk for PTL, so all patients can be managed as being at risk.
585:, termed Dichorionic-Diamniotic or "DiDi". It occurs in almost all cases of dizygotic twins (except in very rare cases of fusion between their blastocysts) and in 18–36% (or around 25%) of
1307:
influence. Twins that have been separated early in life and raised in separate households are especially sought-after for these studies, which have been used widely in the exploration of
1131:, mystifyingly, was not the mother of two of her three children; she was found to be a chimera, and the two children were conceived from eggs derived from cells of their mother's twin.
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Twin-to-twin transfusion syndrome (TTTS) illustration of twins showing one fetus with exposure to more amniotic fluid while the other is "stuck" with the membrane tightly around itself
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around 4–5) to 15 and more per thousand in some parts of India and up to over 20 in some
Central African countries. The exact cause for the splitting of a zygote or embryo is unknown.
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516:
arise from sesquizygotic (semi-identical) twinning which happens when a single egg is fertilized by two sperm and splits the three sets of chromosomes into two separate cell sets.
441:
Monozygotic twins, although genetically very similar, are not genetically exactly the same. The DNA in white blood cells of 66 pairs of monozygotic twins was analyzed for 506,786
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1940:
1328:. One 1992 study estimates that the frequency of heteropaternal superfecundation among dizygotic twins, whose parents were involved in paternity suits, was approximately 2.4%.
619:(called Monochorionic-Diamniotic "MoDi"), which occurs in 60–70% of the pregnancies with monozygotic twins, and in 0.3% of all pregnancies. Monochorionic-Diamniotic twins are
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showed that although its fetal development suggested that it was an identical twin, as it shared a placenta with its healthy twin, tests revealed that it was probably a
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O. Bomsel-Helmreich; W. Al Mufti (1995). "The mechanism of monozygosity and double ovulation". In Louis G. Keith; Emile
Papierik; Donald M. Keith; Barbara Luke (eds.).
155:, the lowest rates are found; only 6 to 9 twin sets per 1,000 live births. North America and Europe have intermediate rates of 9 to 16 twin sets per 1,000 live births.
1375:(45,X). In these cases, although the twins did form from the same fertilized egg, it is incorrect to refer to them as genetically identical, since they have different
2075:
806:
305:. Dizygotic twinning ranges from six per thousand births in Japan (similar to the rate of monozygotic twins) to 14 and more per thousand in some African countries.
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have the highest rate of twinning in the world, at 45–50 twin sets (90–100 twins) per 1,000 live births, possibly because of high consumption of a specific type of
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Schmid, O; Trautmann, U; Ashour, H; Ulmer, R; Pfeiffer, RA; Beinder, E (Dec 2000). "Prenatal diagnosis of heterokaryotypic mosaic twins discordant for fetal sex".
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246:(also referred to as "non-identical twins", "dissimilar twins", "biovular twins", and, informally in the case of females, "sororal twins") usually occur when two
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Girela, Eloy; Lorente, Jose A.; Alvarez, J. Carlos; Rodrigo, Maria D.; Lorente, Miguel; et al. (1997). "Indisputable double paternity in dizygous twins".
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1260:. Ectopic pregnancies must be resolved because they can be life-threatening to the mother. However, in most cases, the intrauterine pregnancy can be salvaged.
426:. Normally due to an environmental factor or the deactivation of different X chromosomes in female monozygotic twins, and in some extremely rare cases, due to
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Nieuwint, Aggie; Van Zalen-Sprock, Rieteke; Hummel, Pieter; Pals, Gerard; Van Vugt, John; et al. (1999). "'Identical' twins with discordant karyotypes".
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Various types of chorionicity and amniosity (how the baby's sac looks) in monozygotic (one egg/identical) twins as a result of when the fertilized egg divides
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early in pregnancy, yet the pregnancy will continue; one twin was miscarried but the other was able to be carried to term. This occurrence is similar to the
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from various parts of the body. The number of cells derived from each fetus can vary from one part of the body to another, and often leads to characteristic
847:. In Cândido Godói, one in five pregnancies has resulted in twins. The Argentine historian Jorge Camarasa has put forward the theory that experiments of the
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level of experience of the obstetrician, the wish of the women giving birth, or the "management strategies" of the procedure of delivering the second twin.
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The widespread use of fertility drugs causing hyperovulation (stimulated release of multiple eggs by the mother) has caused what some call an "epidemic of
4114:; (3) when either of the twins had died in the womb before the onset of labor; and (4) when the pregnancy had been complicated by fetal malformations or
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Stein W, Misselwitz B, Schmidt S (2008). "Twin-to-twin delivery time interval: influencing factors and effect on short-term outcome of the second twin".
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towards the other. Sometimes the parasitic twin becomes an almost indistinguishable part of the other, and sometimes this needs to be treated medically.
289:. Dizygotic twins share on average 50 percent of each other's genes, the same as siblings that are conceived and born at different times. Like any other
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and procedures such as IVF, which result in multiple births more frequently than unassisted fertilizations do. It may also be linked to the increase of
789:
From 1980 to 1997, the number of twin births in the United States rose 52%. This rise can at least partly be attributed to the increasing popularity of
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Matte, U; Le Roux, MG; Bénichou, B; Moisan, JP; Giugliani, R (1996). "Study on possible increase in twinning rate at a small village in south Brazil".
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is an exceedingly rare type of dizygotic twinning in which one twin implants in the uterus as normal and the other remains in the fallopian tube as an
4892:
123:
The human twin birth rate in the United States rose 76% from 1980 through 2009, from 9.4 to 16.7 twin sets (18.8 to 33.3 twins) per 1,000 births. The
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Guinness World Record holding twins: https://www.guinnessworldrecords.com/news/2022/11/theyre-so-different-even-though-theyre-identical-twins-725135
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297:, particularly as they are the same age. However, dizygotic twins may also look very different from each other (for example, be of opposite sexes).
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3111:
Scott, Richard T.; Treff, Nathan R.; Stevens, John; Forman, Eric J.; Hong, Kathleen H.; Katz-Jaffe, Mandy G.; Schoolcraft, William B. (June 2012).
2580:"Time-lapse recordings reveal why IVF embryos are more likely to develop into twins. Researchers believe the laboratory culture could be the cause"
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male. The exact mechanism of fertilization could not be determined but the study stated that it was unlikely to be a case of polar body twinning.
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who happen to develop in the womb together and who are born at the same time, since they arise from two separate eggs fertilized by two separate
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Orwant, Jon. "Heterogeneous learning in the
Doppelgänger user modeling system." User Modeling and User-Adapted Interaction 4.2 (1994): 107-130.
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contains two inner cell masses (ICM), each of which will lead to a separate fetus, rather than by the embryo splitting while hatching from the
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and the cell divides into two, with each daughter cell now containing the correct number of chromosomes. The cells continue to develop into a
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Comparison of zygote development in monozygotic and dizygotic twins. In the uterus, a majority of monozygotic twins (60–70%) share the same
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5116:(Palgrave Macmillan; 2010) 221 pages; explores the experience of child twins, adult twins, and parents of twins, with a focus on Britain.
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1407:. If the morula then undergoes a twinning event, two embryos will be formed, with different paternal genes but identical maternal genes.
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Gedda, Luigi (1995). "The role of research in twin medicine". In Louis G. Keith; Emile Papiernik; Donald M. Keith; Barbara Luke (eds.).
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is recommended at between 37 and 38 weeks. Vaginal delivery in this case does not worsen the outcome for the infant as compared with
5241:""Masculinizing" effect on respiratory morbidity in girls from unlike-sex preterm twins: a possible transchorionic paracrine effect"
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Sometimes one twin fetus will fail to develop completely and continue to cause problems for its surviving twin. One fetus acts as a
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DiDi twins have the lowest mortality risk at about 9 percent, although that is still significantly higher than that of singletons.
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IVF techniques are more likely to create dizygotic twins. For IVF deliveries, there are nearly 21 pairs of twins for every 1,000.
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4000:
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monozygotic twinning, a 2007 theory related to in vitro fertilization (IVF) proposes that monozygotic twins may be formed when a
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R. Derom; J. Orlebeke; A. Eriksson; M. Thiery (1995). "The epidemiology of multiple births in Europe". In Louis G. Keith (ed.).
1798:
4321:
Biswas, A; Su, LL; Mattar, C (Apr 2013). "Caesarean section for preterm birth and, breech presentation and twin pregnancies".
3493:
185:
Female-male twins: This is the most common pairing (50%), encompassing both "female-male" (25%) and "male-female" (25%) twins.
5348:
4696:
4178:
3634:
3585:
3431:
3360:
2933:
2754:
2335:
1916:
1795:
Martin, Joyce A.; Hamilton, Brady E.; Osterman, Michelle J.K. "Three Decades of Twin Births in the United States, 1980–2009"
5458:
2105:
811:
4826:
4196:
2498:
2067:
969:
1828:
1050:
syndrome. Also, in an unknown proportion of cases, two zygotes may fuse soon after fertilization, resulting in a single
996:
yielded a mean delivery time interval of 13.5 minutes. The delivery interval between the twins was measured as follows:
4451:
5496:
4684:
2579:
2354:
Bortolus, Renata; Fabio Parazzini; Liliane Chatenoud; Guido Benzi; Massimiliano Maria Bianchi; Alberto Marini (1999).
281:
Dizygotic twins, like any other siblings, will practically always have different sequences on each chromosome, due to
5578:
5499:, who are twins and joined the Army on a same day, were promoted to the rank of Major General, again on the same day.
4572:
4115:
4026:
Kulkarni, A. D.; Jamieson, D. J.; Jones, H. W. Jr.; Kissin, D. M.; Gallo, M. F.; MacAluso, M.; Adashi, E. Y. (2013).
3951:
3252:
2900:
1563:
1211:
672:
635:
294:
5240:
4467:"Prospective risk of stillbirth and neonatal complications in twin pregnancies: systematic review and meta-analysis"
3029:
1311:. Classical twin studies are now being supplemented with molecular genetic studies which identify individual genes.
250:
eggs are implanted in the uterus wall at the same time. When two eggs are independently fertilized by two different
5673:
5583:
2275:
958:
1611:
increased output of twins during periods of evolutionary distress and natural selection. Through their studies on
449:
4285:
2828:
Fraga, Mario F.; Ballestar, Esteban; Paz, Maria F.; Ropero, Santiago; Setien, Fernando; et al. (July 2005).
1849:
17:
442:
5527:
2523:
2706:
Machin, GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs".
777:
present in dairy products may increase the chance of dizygotic twinning. Specifically, the study found that
4900:
3170:"Postzygotic diploidization of triploids as a source of unusual cases of mosaicism, chimerism and twinning"
1699:
752:
3763:
2126:
1878:
1590:
responsible for the likelihood of twins, rather than the likelihood of litters (Whitcomb, 2021). Cases of
1202:. There is an increased possibility of potential complications as the birth weight of the baby decreases.
366:
Monozygotic twins may also be created artificially by embryo splitting. It can be used as an expansion of
2250:
2215:
931:
Dizygotic twin pregnancies are slightly more likely when the following factors are present in the woman:
4465:
Cheong-See F, Schuit E, Arroyo-Manzano D, Khalil A, Barrett J, Joseph KS, et al. (September 2016).
3949:
3855:
4355:
1762:
786:
is given to cattle, appear to enhance the chances of multiple pregnancies due to ovarian stimulation."
774:
543:
3533:
2538:
5013:
2425:
1166:, resulting in little or no fetus and a cancerous, overgrown placenta, resembling a bunch of grapes.
1042:
748:
701:
Mortality is highest for conjoined twins due to the many complications resulting from shared organs.
5214:
4787:
3423:
3411:
5520:
1534:
1446:
4516:"Co-bedding in neonatal nursery for promoting growth and neurodevelopment in stable preterm twins"
2205:
343:. The chances of having identical twins is relatively rare — around 3 or 4 in every 1,000 births.
5611:
5044:
3885:
3204:
1654:
1538:
458:
382:
Monozygotic twinning occurs in birthing at a rate of about 3 in every 1000 deliveries worldwide.
45:
Identical twins can be difficult to visually distinguish when young, as demonstrated by brothers
3113:"Delivery of a chromosomally normal child from an oocyte with reciprocal aneuploid polar bodies"
1729:
5435:
5209:
4993:
4368:
3509:
3352:
2403:
965:
964:
The risk of twin birth can vary depending on what types of fertility treatments are used. With
367:
35:
5094:
Hayashi, C (2007). "Relationship between Twin Language, Twins' Bond, and Social Competence".
5014:"What are mirror image twins? | Washington State Twin Registry | Washington State University"
4257:"Very Low Birthweight - Online Medical Encyclopedia - University of Rochester Medical Center"
2537:
Oleszczuk, Jaroslaw J.; Donald M. Keith; Louis G. Keith; William F. Rayburn (November 1999).
2305:
1253:
683:
Monoamniotic twins occur when the split takes place after the ninth day after fertilization.
474:
However, certain characteristics become more alike as twins age, such as IQ and personality.
282:
46:
31:
3344:
5439:
5406:
5299:
4227:
3069:
2841:
2426:"Study: Time-lapse recordings reveal why IVF embryos are more likely to develop into twins"
1983:
1591:
1497:
1072:
790:
435:
2240:
992:
A 15-year German study of 8,220 vaginally delivered twins (that is, 4,110 pregnancies) in
732:
with the head pointing towards upper left. The twin at right in the image is shown in the
8:
5570:
3570:
1419:
1304:
604:
5303:
4659:
3253:"Semi-identical twins are rare, and doctors say they've identified the second case ever"
3073:
2977:
Gudmundur L. (2021-01-07). "Differences between germline genomes of monozygotic twins".
2845:
2536:
1987:
5642:
5588:
5398:
5386:
5322:
5287:
5268:
5188:
5145:
4873:
4629:
4604:
4548:
4515:
4491:
4466:
4419:
4394:
4166:
4092:
3950:
Fernand Leroy; Taiwo Olaleye-Oruene; Gesina Koeppen-Schomerus; Elizabeth Bryan (2002).
3932:
3920:
3691:
3300:
3220:
3145:
3112:
3085:
3010:
2864:
2829:
2810:
2766:
2683:
2658:
2634:
2609:
2245:
2210:
2006:
1971:
1704:
1649:
1595:
knowledge, this is the first report of monozygotic twinning in the dog confirmed using
1462:
1442:
1427:
1343:
1163:
1109:
1051:
844:
647:
5223:
3382:
3288:
5390:
5354:
5344:
5327:
5260:
5227:
5180:
5137:
5061:
5057:
4976:
4865:
4769:
4702:
4692:
4634:
4553:
4535:
4496:
4424:
4338:
4174:
4111:
4084:
4049:
3971:
3924:
3683:
3648:
3640:
3630:
3589:
3545:
3534:"Mechanisms of twinning: VII. Effect of diet and heredity on the human twinning rate"
3470:
3427:
3356:
3345:
3304:
3292:
3191:
3150:
3132:
3093:
3058:
3014:
3002:
2994:
2939:
2929:
2906:
2896:
2889:
2869:
2802:
2758:
2723:
2688:
2639:
2550:
2517:
2479:
2474:
2457:
2385:
2377:
2331:
2187:
2046:
2011:
1967:
1912:
1882:
1600:
1415:
1273:
1257:
843:
to 10% for Linha São Pedro, a tiny Brazilian settlement which belongs to the city of
513:
497:
5272:
5192:
5149:
4096:
3936:
3695:
3224:
2770:
1796:
595:
Dichorionic-Diamniotic twins form when splitting takes place by the third day after
5683:
5678:
5462:
5402:
5382:
5317:
5307:
5252:
5219:
5170:
5129:
5053:
4966:
4877:
4857:
4759:
4749:
4624:
4616:
4543:
4531:
4527:
4486:
4478:
4414:
4406:
4367:. Royal College of Obstetricians and Gynaecologist. pp. 70–103. Archived from
4330:
4076:
4039:
3963:
3916:
3675:
3490:
3460:
3284:
3212:
3181:
3140:
3124:
3077:
2986:
2859:
2849:
2814:
2794:
2750:
2715:
2678:
2670:
2629:
2621:
2469:
2367:
2353:
2179:
2038:
2001:
1991:
1689:
1612:
1578:
1350:, which exhibit differing ethnic and racial features. One such pairing was born in
1325:
1269:
1195:
968:(IVF), this is primarily due to the insertion of multiple embryos into the uterus.
879:
574:
81:
4334:
2798:
2625:
5598:
5000:
4410:
4356:
National Collaborating Centre for Women's and Children's Health (November 2011).
4170:
3747:
3516:
3497:
3407:
2957:
Mandler, G (2001). "Apart from genetics: What makes monozygotic twins similar?".
2097:
1996:
1802:
1736:
1664:
1372:
1268:
For otherwise healthy twin pregnancies where both twins are head down a trial of
1128:
1063:
706:
688:
539:
483:
371:
198:
is higher for twins, it leads to female twins being more common than male twins.
128:
5239:
Shinwell ES, Reichman B, Lerner-Geva L, Boyko V, Blickstein I (September 2007).
4924:"Doctors say they have identified rare set of semi-identical twins in Australia"
2170:
Nylander, Percy P. S. (July 1981). "The Factors That Influence Twinning Rates".
2029:
Elliott, JP (December 2008). "Preterm labor in twins and high-order multiples".
1639:
1465:
lethality, while the other two cell lines, each consisting of the same maternal
397:
182:
Male–male twins: Sometimes called fraternal (unrelated to zygosity) twins (25%).
112:
5637:
5606:
5292:
Proceedings of the National Academy of Sciences of the United States of America
4514:
Lai, Nai Ming; Foong, Siew Cheng; Foong, Wai Cheng; Tan, Kenneth (2016-04-14).
2990:
1679:
1545:
1485:
1199:
1179:
1140:
1047:
1035:
891:
794:
783:
760:
729:
676:
501:
360:
152:
140:
100:
5479:"Twin Zygosity Test for Dichorionic Diamniotic (Di/Di) Twins! Zygosity Reveal"
5175:
5158:
4971:
4954:
4861:
4818:
4395:"Trends in caesarean delivery for twin births in the United States: 1995-2008"
4080:
3679:
3128:
2183:
2042:
1817:
1216:
414:
same person), rather than first cousins. Identical twins do not have the same
5668:
5662:
5616:
5358:
4706:
4539:
4443:
3750:
3644:
3136:
2998:
2381:
2372:
2355:
1659:
1596:
1581:, because while litters are caused by the release of multiple eggs during an
1458:
1400:
940:
895:
883:
852:
840:
831:
About 1 in 90 human births (1.1%) results from a twin pregnancy. The rate of
824:
756:
733:
725:
698:
into 2 embryos occurs, 99% of the time it is within 8 days of fertilization.
596:
247:
144:
132:
124:
5312:
3652:
3449:"Monochorionic diamniotic infants without twin-to-twin transfusion syndrome"
3186:
3169:
3081:
2943:
2910:
2854:
5394:
5331:
5264:
5256:
5141:
5065:
4869:
4773:
4710:
4577:
4557:
4500:
4428:
4342:
4088:
4053:
3975:
3593:
3549:
3474:
3419:
3296:
3195:
3154:
3006:
2873:
2806:
2762:
2720:
10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S
2643:
2587:
2554:
2483:
2389:
2050:
2015:
1709:
1502:
1435:
1308:
1230:
1191:
906:
671:
Monoamniotic twins, as with diamniotic monochorionic twins, have a risk of
668:
The survival rate for monoamniotic twins is somewhere between 50% and 60%.
616:
582:
406:
251:
5231:
5184:
4980:
4754:
4737:
4044:
4027:
3967:
3928:
3789:"Seeing double: the village in deepest Kerala where twins have taken over"
3687:
3465:
3448:
3097:
2727:
2692:
2456:
Illmensee K, Levanduski M, Vidali A, Husami N, Goudas VT (February 2009).
2191:
224:
5647:
4738:"Molecular Support for Heterogonesis Resulting in Sesquizygotic Twinning"
4638:
3216:
2430:
1674:
1506:
1441:
The likely genetic basis of semi-identical twins was reported in 2019 by
1387:
1347:
1337:
1175:
973:
936:
898:, the twinning rate exceeded 3% of all births. Nevertheless, the rate of
662:
586:
470:
466:
415:
5134:
10.1002/(SICI)1097-0223(199901)19:1<72::AID-PD465>3.0.CO;2-V
4764:
4620:
2674:
1805:, National Center for Health Statistics Data Brief, No. 80, January 2012
1461:
to form three cell lines. The purely paternal cell line died out due to
1303:
characteristics to try to isolate genetic influence from epigenetic and
984:) has a relatively less but yet significant risk of multiple pregnancy.
4603:
Schmidt, R; EH Sobel; HM Nitowsky; H Dar; FH Allen Jr (February 1976).
3275:
3089:
2975:
2830:"Epigenetic differences arise during the lifetime of monozygotic twins"
2325:
1694:
1684:
1669:
1300:
1285:
1241:
624:
505:
454:
427:
356:
148:
143:, there are 18–30 twin sets (or 36–60 twins) per 1,000 live births. In
108:
4482:
3907:
Rehan N, Tafida DS (November 1980). "Multiple births in Hausa women".
3030:"Identical twins aren't always genetically identical, new study finds"
2539:"Projections of population-based twinning rates through the year 2100"
1068:
216:
1644:
1582:
1376:
1182:
syndrome, but typically occurs later, as the twin is not reabsorbed.
1159:
1116:
977:
836:
755:
of 15 weeks. There is no sign of any membrane between the fetuses. A
431:
278:, just like ordinary siblings. This is the most common type of twin.
160:
61:
57:
5368:"Selection for Increased Brood Size in Historical Human Populations"
4464:
2755:
10.1002/1097-0223(200012)20:12<999::aid-pd948>3.0.co;2-e
1123:, composed of cells from a male twin and a female twin. In one case
763:
of parts of the upper thorax and head is shown of the twin at right.
5552:
4393:
Lee HC, Gould JB, Boscardin WJ, El-Sayed YY, Blumenfeld YJ (2011).
4323:
Best Practice & Research. Clinical Obstetrics & Gynaecology
4163:
Multiple Pregnancy: Epidemiology, Gestation & Perinatal Outcome
2328:
Multiple Pregnancy: Epidemiology, Gestation & Perinatal Outcome
2157:"Chinese Women Try to Bypass One-Child Policy With Pills for Twins"
1909:
Multiple Pregnancy: Epidemiology, Gestation & Perinatal Outcome
1431:
1296:
1146:
1124:
1120:
1076:
860:
778:
631:
610:
550:
423:
402:
201:
5512:
5459:"Facts About Multiples: An Encyclopedia of Multiple Birth Records"
5119:
2458:"Human embryo twinning with applications in reproductive medicine"
1814:
4927:
3626:
3446:
1634:
1616:
1410:
1292:
914:
910:
869:
864:
819:
twin figures (early 20th-century) in the permanent collection of
705:
If the division of the zygote occurs later than the 12 days then
578:
478:
290:
286:
271:
5238:
2891:
Entwined lives: twins and what they tell us about human behavior
972:
without IVF has a very high risk of multiple birth. Reversal of
5042:
Thorpe, K (June 2006). "Twin children's language development".
4602:
4131:"I'll do it my way: twin is born three months after her sister"
4028:"Fertility Treatments and Multiple Births in the United States"
3447:
Cordero L, Franco A, Joy SD, O'Shaughnessy RW (December 2005).
2455:
2302:"Identical and Fraternal Twins – Determining Zygosity in Twins"
1587:
1470:
1404:
1367:
clinical determination that the multiples are not monozygotic.
1351:
1226:
873:
695:
653:
526:
340:
336:
259:
205:
92:
73:
69:
3711:"Nazi Angel of death Josef Mengel created twin town in Brazil"
3519:
By Pamela Prindle Fierro, About.com. Retrieved on July 9, 2009
1906:
1815:
Zach, Terence; Arun K Pramanik; Susannah P Ford (2007-10-02).
928:
The predisposing factors of monozygotic twinning are unknown.
728:
as part of IVF. The twin at left in the image is shown in the
41:
5365:
5341:
Identical Strangers: A Memoir of Twins Separated and Reunited
1823:
1450:
1396:
1097:
1093:
1089:
1085:
993:
839:, ranging as high as about 45 per 1000 births (4.5%) for the
816:
275:
136:
111:
whose resemblance parallels that of twins are referred to as
88:
2406:. MedlinePlus, US National Library of Medicine. 11 July 2022
2404:"Is the probability of having twins determined by genetics?"
1603:
and geographical population diffusion of armadillo species.
1457:
simultaneously. The chromosomes assorted themselves through
1233:. The lives of both twins are endangered by this condition.
477:
In January 2021, new research from a team of researchers in
339:(hence, "monozygotic") which then divides into two separate
5199:
4025:
1454:
1392:
848:
363:(the gelatinous protective coating around the blastocyst).
332:
302:
3665:
3414:. In Robert Resnik; Robert K. Creasy; Jay D. Iams (eds.).
2740:
1933:"What's in a yam? Clues to fertility, a student discovers"
461:
have become distinguishable from each other by adulthood.
179:
Female–female twins: Sometimes called sororal twins (25%).
4788:"Rare new kind of twins: boy and girl are semi-identical"
4392:
1466:
807:
Populated places with highest incidence of multiple birth
724:
Dichorionic-diamniotic twins at 8 weeks and 5 days since
465:
Another cause of difference between monozygotic twins is
5288:"Male twins reduce fitness of female co-twins in humans"
5156:
4846:
3741:
Nazi 'Angel of Death' not responsible for town of twins
3110:
2827:
1382:
1357:
1079:) in 1811, were the origin of the term "Siamese twins".
4066:
2172:
Acta Geneticae Medicae et Gemellologiae: Twin Research
1965:
827:
have the highest dizygotic twinning rate in the world.
491:
370:(IVF) to increase the number of available embryos for
5338:
4748:(9). Boston: Massachusetts Medical Society: 842–849.
4736:
Gabbett, Michael T.; et al. (28 February 2019).
3568:
2783:
2584:
European Society of Human Reproduction and Embryology
4893:"Study describes new type of "semi-identical" twins"
1205:
1119:
skin coloration in human chimeras. A chimera may be
920:
Twins are more common in people of African descent.
392:
5495:Twin brothers promoted as Majors General together.
5285:
27:
One of two offspring produced by the same pregnancy
5366:Helle, Samuli; Virpi Lummaa; Jukka Jokela (2004).
5159:"How frequent is heteropaternal superfecundation?"
5114:Twins in Society: Parents, Bodies, Space, and Talk
4953:Gedda L, Sciacca A, Brenci G, et al. (1984).
4952:
4195:
4129:
2888:
1816:
902:twins remains at about 1 in 333 across the globe.
95:(the much more common case in humans) is called a
68:('identical'), meaning that they develop from one
5003:. Proactivegenetics.com. Retrieved on 2013-08-10.
3486:
3484:
2304:. Multiples.about.com. 2013-07-16. Archived from
1752:in "Human Heredity Principles and issues" p. 104.
1024:
270:. Fraternal twins are, essentially, two ordinary
5660:
5157:Wenk RE, Houtz T, Brooks M, Chiafari FA (1992).
4994:Twins genetics, details of environmental impacts
4955:"Situs viscerum specularis in monozygotic twins"
4513:
3952:"Yoruba Customs and Beliefs Pertaining to Twins"
3878:"Mohammadpur Umri, THE VILLAGE OF TWINS !!"
3416:Maternal-Fetal Medicine: Principles and Practice
3351:. Washington, DC: Taylor & Francis. p.
2278:. Washington State Twin Registry. October 2015.
1354:in 1993 to a white mother and Caribbean father.
1229:, the other, the 'recipient' twin, is large and
1190:It is very common for twins to be born at a low
312:
4441:
3569:Martin, Joyce A; Melissa M. Park (1999-09-14).
3342:
2656:
1763:"Twins, Triplets, Multiple Births: MedlinePlus"
573:Normally, twins have two separate (di- being a
4320:
4286:"Pregnant with twins: potential complications"
3620:
3481:
3202:
3027:
1496:There have been many studies highlighting the
1469:but only 50% identical paternal DNA, formed a
211:
99:, and the general term for one offspring of a
5528:
5286:Lummaa V, Pettay JE, Russell AF (June 2007).
3376:
3374:
3372:
3117:Journal of Assisted Reproduction and Genetics
2490:
949:She is greater than average height and weight
623:monozygotic, with a few exceptions where the
175:Fraternal twins can be any of the following:
4458:
4386:
4349:
3571:"Trends in Twin and Triplet Births: 1980–97"
3510:MoMo Twins; Monochorionic Monoamniotic Twins
2777:
2610:"Mechanical control of tissue morphogenesis"
2276:"Are there more male twins or female twins?"
905:In a study on the maternity records of 5750
5079:Usher, L (13 October 2000). "Idioglossia".
4520:The Cochrane Database of Systematic Reviews
3906:
3884:. Business Directory Plugin. Archived from
3623:Progress in Reproductive Medicine Volume II
2349:
2347:
1324:This phenomenon is known as heteropaternal
894:". In 2001, for the first time ever in the
512:In 2003, a study argued that many cases of
453:Despite being genetically identical, twins
254:, fraternal twins result. The two eggs, or
5535:
5521:
4816:
4316:
4314:
4312:
4310:
3708:
3406:
3369:
3338:
3336:
3334:
3332:
3330:
3328:
3167:
2734:
2607:
2505:. Archived from the original on 2001-05-27
1723:
5321:
5311:
5213:
5174:
4970:
4763:
4753:
4628:
4547:
4490:
4418:
4193:
4127:
4043:
3491:Pregnancy-Info -- > Monoamniotic Twins
3464:
3185:
3144:
2863:
2853:
2682:
2633:
2473:
2371:
2068:"Probability of having twins hereditary?"
2005:
1995:
1564:Learn how and when to remove this message
1548:so that sources are clearly identifiable.
952:She has had several previous pregnancies.
946:She is between the age of 30 and 40 years
656:in 1–2% of monozygotic twin pregnancies.
4691:. Sunderland, Mass: Sinauer Associates.
4570:
4007:. University of Rochester Medical Center
3531:
3527:
3525:
2657:Edwards JH, Dent T, Kahn J (June 1966).
2496:
2344:
2169:
1961:
1959:
1957:
1850:"Genetics or yams in the Land of Twins?"
1409:
1248:
1215:
1067:
810:
525:
448:
396:
223:
215:
40:
5339:Schein, Elyse; Paula Bernstein (2007).
5163:Acta Geneticae Medicae et Gemellologiae
5093:
4899:. Thomson Reuters Trust. Archived from
4884:
4735:
4731:
4729:
4727:
4682:
4307:
4154:
3440:
3325:
2956:
2028:
1491:
923:
615:Monochorionic twins generally have two
519:
422:Monozygotic twins always have the same
228:Fraternal twin brothers as young babies
14:
5661:
5041:
4921:
4890:
4605:"Monozygotic twins discordant for sex"
3380:
2923:
2895:. New York: Dutton. pp. 135–138.
2705:
2133:. Associated Press. 14 February 2006.
1972:"Twinning across the Developing World"
1399:. The cell assorts the chromosomes by
1263:
1152:
549:It is a common misconception that two
5516:
5078:
4798:from the original on 28 February 2019
4794:. Thomson Reuters. 28 February 2019.
4194:Ainsworth, Chris (15 November 2003).
4160:
3900:
3621:Asch, Richard H.; John Studd (1995).
3586:National Center for Health Statistics
3522:
3503:
2886:
2356:"The epidemiology of multiple births"
2294:
2095:
1954:
1478:
1473:which subsequently split into twins.
1279:
909:women living in the Savannah zone of
821:The Children's Museum of Indianapolis
430:, twins may express different sexual
166:
159:genetically linked tendency to hyper-
139:to release an egg from each side. In
4724:
4442:James Gallagher (23 November 2011).
4060:
3614:
3265:
3231:from the original on 29 October 2021
3040:from the original on 11 January 2021
2708:American Journal of Medical Genetics
2659:"Monozygotic twins of different sex"
2543:The Journal of Reproductive Medicine
2268:
2137:from the original on 6 December 2008
1970:(2011). Newell, Marie-Louise (ed.).
1517:
1383:Semi-identical (sesquizygotic) twins
1358:Monozygotic twins of different sexes
1319:
1314:
1174:Occasionally, a woman will suffer a
987:
759:is shown of the twin at left, and a
694:When the division of the developing
5542:
4142:from the original on 30 August 2021
3828:from the original on 29 August 2018
3422:: W. B. Saunders Company. pp.
3205:"'Semi-identical' twins discovered"
2396:
2330:. Taylor and Francis. p. 145.
2127:"China: Drug bid to beat child ban"
1750:5-7 Twin Studies and Complex Traits
1739:Last Editorial Review: 19 June 2000
1730:MedicineNet > Definition of Twin
1505:was thought to be the major cause.
1185:
652:Monochorionic twins share the same
630:Monochorionic twins share the same
609:Monochorionic twins share the same
492:Polar body and semi-identical twins
24:
5476:
5456:
5387:10.1111/j.0014-3820.2004.tb01658.x
5106:
4922:Molina, Brett (28 February 2019).
4444:"Women can choose Caesarean birth"
4128:Crossland, David (16 April 2019).
3921:10.1111/j.1471-0528.1980.tb04464.x
3824:. Bennett, Coleman & Co. Ltd.
3168:Golubovsky, M.D. (February 2003).
1911:. Taylor and Francis. p. 34.
1169:
1134:
1057:
1029:
736:with the head pointing rightwards.
25:
5695:
5579:Twin-to-twin transfusion syndrome
5508:
4685:"Non-identical Monozygotic Twins"
4208:from the original on 20 June 2015
4116:Twin-to-twin transfusion syndrome
3578:National Vital Statistics Reports
2282:from the original on 24 July 2018
1212:Twin-to-twin transfusion syndrome
1206:Twin-to-twin transfusion syndrome
1158:results when one twin has either
673:twin-to-twin transfusion syndrome
636:twin-to-twin transfusion syndrome
538:In very rare cases, twins become
393:Genetic and epigenetic similarity
204:is the degree of identity in the
5584:Twin reversed arterial perfusion
5096:Twin Research and Human Genetics
5058:10.1016/j.earlhumdev.2006.03.012
4454:from the original on 2012-08-19.
4110:the first twin was delivered by
4001:"Overview of Multiple Pregnancy"
3721:from the original on 19 May 2019
3385:. Focus Information Technology.
3343:Shulman LS, van Vugt JG (2006).
3203:John Whitfield (26 March 2007).
2608:Patwari P, Lee RT (2008-08-01).
2475:10.1016/j.fertnstert.2008.12.098
2096:Fitch, Karen (26 January 2005).
1546:add missing citation information
1522:
1453:from the same man fertilized an
959:assisted reproductive technology
741:
717:
190:susceptible than females to die
5425:"TWINS Guide to the First Year"
5087:
5072:
5035:
5024:from the original on 2018-09-05
5006:
4987:
4946:
4915:
4840:
4829:from the original on 2023-04-29
4810:
4780:
4742:New England Journal of Medicine
4676:
4645:
4596:
4585:from the original on 2018-01-19
4571:Moorhead, Joanna (2011-09-24).
4564:
4507:
4435:
4296:from the original on 2015-11-09
4278:
4267:from the original on 2018-01-19
4249:
4238:from the original on 2019-04-05
4228:"Risks Linked With Twin Births"
4220:
4187:
4121:
4103:
4032:New England Journal of Medicine
4019:
3993:
3989:– via Randafricanart.com.
3982:from the original on 2017-09-02
3943:
3870:
3840:
3810:
3781:
3770:from the original on 2009-07-18
3766:. BBC World News. 7 June 2001.
3756:
3733:
3702:
3659:
3603:from the original on 2017-11-13
3562:
3400:
3389:from the original on 2008-06-16
3259:
3245:
3161:
3104:
3052:
3021:
2969:
2950:
2917:
2880:
2821:
2699:
2650:
2601:
2572:
2561:from the original on 2009-01-04
2530:
2449:
2438:from the original on 2019-08-05
2418:
2319:
2257:from the original on 2021-07-01
2233:
2222:from the original on 2021-12-12
2198:
2163:
2149:
2119:
2108:from the original on 2022-06-24
2089:
2078:from the original on 2022-09-25
2060:
2022:
1943:from the original on 2022-05-07
1925:
1889:from the original on 2008-12-15
1860:from the original on 2017-02-23
1831:from the original on 2008-09-25
1769:from the original on 2016-06-03
768:
443:single-nucleotide polymorphisms
82:heteropaternal superfecundation
5018:Washington State Twin Registry
4959:Acta Genet Med Gemellol (Roma)
4891:Dunham, Will (26 March 2007).
4532:10.1002/14651858.CD008313.pub3
3854:. 4Skylark.com. Archived from
3709:Nick Evans (21 January 2009).
3668:Acta Genet Med Gemellol (Roma)
2497:Holladay, April (2001-05-09).
1900:
1871:
1842:
1808:
1789:
1780:
1755:
1742:
1363:accepted as a sound basis for
1331:
1236:
1025:Complications during pregnancy
835:twinning varies greatly among
13:
1:
5224:10.1016/S0015-0282(97)81456-2
4335:10.1016/j.bpobgyn.2012.09.002
3795:. 12 May 2009. Archived from
3289:10.1016/s0140-6736(03)14237-7
3028:Lianne Kolirin (8 Jan 2021).
2799:10.1136/jmedgenet-2013-101712
2626:10.1161/CIRCRESAHA.108.175331
1716:
481:was published in the journal
313:Monozygotic (identical) twins
118:
72:, which splits and forms two
4411:10.1097/AOG.0b013e3182318651
2959:Journal of Mind and Behavior
2834:Proc. Natl. Acad. Sci. U.S.A
2586:. 2007-07-02. Archived from
1997:10.1371/journal.pone.0025239
1700:Twin towns and sister cities
1103:
800:
773:A 2006 study has found that
377:
346:
7:
4930:. USA TODAY. Archived from
4817:NEJM Group (4 March 2019).
4609:Journal of Medical Genetics
3848:"Twin Capital Of The World"
3532:Steinman, Gary (May 2006).
3381:Curran, Mark (2005-11-02).
2663:Journal of Medical Genetics
2251:Central Intelligence Agency
2216:Central Intelligence Agency
2159:. ABC News. August 3, 2011.
1627:
1054:embryo, and, later, fetus.
751:of monoamniotic twins at a
496:A 1981 study of a deceased
438:zygote splitting unevenly.
212:Dizygotic (fraternal) twins
194:, and since the death rate
91:that develops alone in the
10:
5700:
5343:. New York: Random House.
4683:Gilbert, Scott F. (2006).
2991:10.1038/s41588-020-00755-1
1513:
1335:
1283:
1209:
1138:
1107:
1061:
1033:
804:
775:insulin-like growth factor
648:Monochorionic-Monoamniotic
634:, and thus have a risk of
335:is fertilized to form one
29:
5630:
5597:
5569:
5551:
5176:10.1017/S000156600000249X
5081:Times Literary Supplement
4972:10.1017/S0001566000007546
4862:10.1007/s00439-006-0279-x
4081:10.1080/00016340801934276
4069:Acta Obstet Gynecol Scand
3680:10.1017/S0001566000000829
3500:Retrieved on July 9, 2009
3129:10.1007/s10815-012-9746-6
2522:: CS1 maint: unfit URL (
2499:"What triggers twinning?"
2360:Human Reproduction Update
2184:10.1017/s0001566000007650
2043:10.1016/j.clp.2007.10.004
1346:couples can sometimes be
1127:determined that a woman,
1043:obstetric ultrasonography
856:of the world, including:
749:Abdominal ultrasonography
351:Regarding spontaneous or
4819:"Sesquizygotic Twinning"
2928:. New York: Worth Pubs.
2887:Segal, Nancy L. (1999).
2104:. The Tech Interactive.
1000:Within 15 minutes: 75.8%
970:Ovarian hyperstimulation
709:are usually the result.
605:Monochorionic-Diamniotic
135:which may stimulate the
5674:Reproduction in mammals
5612:Craniopagus parasiticus
5313:10.1073/pnas.0605875104
5202:Fertility and Sterility
5045:Early Human Development
4573:"Black and white twins"
3753:online, 27 January 2009
3082:10.1126/science.7196086
2924:Plomin, Robert (2001).
2855:10.1073/pnas.0500398102
2206:"United States: People"
2074:. Columbia University.
2031:Clinics in Perinatology
1655:List of multiple births
1498:development of language
980:(trade names including
679:due to lack of oxygen.
658:Monoamniotic twins are
570:Dichorionic-Diamniotic
544:pregnancy complications
467:epigenetic modification
434:, normally from an XXY
5438:. 2008. Archived from
5436:Fort Collins, Colorado
5257:10.1542/peds.2006-3574
4261:www.urmc.rochester.edu
2373:10.1093/humupd/5.2.179
1937:Yale Medicine Magazine
1422:
1221:
1080:
966:in vitro fertilisation
828:
531:
462:
410:
368:in vitro fertilization
229:
221:
64:. Twins can be either
50:
36:Twins (disambiguation)
4755:10.1056/NEJMoa1701313
4689:Developmental biology
4653:"The Zygosity Puzzle"
4197:"The stranger within"
4045:10.1056/NEJMoa1301467
3968:10.1375/1369052023009
3466:10.1038/sj.jp.7211405
3187:10.1093/humrep/deg060
1748:Michael R. Cummings,
1660:List of notable twins
1413:
1395:is fertilized by two
1342:Dizygotic twins from
1254:Heterotopic pregnancy
1249:Heterotopic pregnancy
1219:
1162:or complete paternal
1071:
1012:Over 60 minutes: 1.8%
814:
529:
452:
400:
283:chromosomal crossover
227:
220:Adult fraternal twins
219:
131:containing a natural
60:produced by the same
47:Billy and Bobby Mauch
44:
32:Twin (disambiguation)
5497:Seneviratne brothers
3909:Br J Obstet Gynaecol
3818:"A village of twins"
3412:"Multiple Gestation"
3217:10.1038/news070326-1
2614:Circulation Research
1592:monozygotic twinning
1533:needs more complete
1492:Language development
1075:, born in Siam (now
1073:Chang and Eng Bunker
1003:16–30 minutes: 16.4%
939:descent (especially
924:Predisposing factors
520:Degree of separation
436:Klinefelter syndrome
331:occur when a single
30:For other uses, see
5571:Monochorionic twins
5304:2007PNAS..10410915L
4934:on 28 February 2019
4903:on 28 February 2019
4621:10.1136/jmg.13.1.64
4358:"Caesarean section"
4005:Health Encyclopedia
3764:"The Land Of Twins"
3074:1981Sci...213..775B
2926:Behavioral genetics
2846:2005PNAS..10210604F
2675:10.1136/jmg.3.2.117
1988:2011PLoSO...625239S
1879:"The Land of Twins"
1420:Miles City, Montana
1414:Twin calves of the
1264:Management of birth
1153:Partial molar twins
1009:46–60 minutes: 1.7%
1006:31–45 minutes: 4.3%
589:(identical) twins.
5589:Monoamniotic twins
5457:Samson, Jennifer.
5122:Prenatal Diagnosis
4999:2021-08-31 at the
4167:Taylor and Francis
3746:2014-10-25 at the
3515:2016-04-08 at the
3496:2019-11-03 at the
3174:Human Reproduction
2246:The World Factbook
2211:The World Factbook
1854:Independent Online
1801:2017-12-18 at the
1735:2013-10-22 at the
1705:Twins in mythology
1650:Gemini (astrology)
1479:Mirror image twins
1463:genomic imprinting
1423:
1280:Human twin studies
1222:
1164:uniparental disomy
1110:Chimera (genetics)
1081:
829:
532:
463:
411:
405:but have separate
293:, dizygotic twins
262:, hence the terms
230:
222:
167:Types and zygosity
51:
5656:
5655:
5350:978-1-4000-6496-0
4698:978-0-87893-250-4
4483:10.1136/bmj.i4353
4180:978-1-85070-666-3
4112:caesarean section
4038:(23): 2218–2225.
3858:on 4 October 2015
3636:978-1-85070-574-1
3433:978-0-7216-0004-8
3362:978-0-8247-2844-1
3347:Prenatal medicine
3068:(4509): 775–777.
2935:978-0-7167-5159-5
2582:(Press release).
2337:978-1-85070-666-3
1968:Christiaan Monden
1918:978-1-85070-666-3
1883:BBC World Service
1818:"Multiple Births"
1601:genetic variation
1574:
1573:
1566:
1320:Bi-paternal twins
1315:Unusual twinnings
1274:Caesarean section
1258:ectopic pregnancy
988:Delivery interval
815:A pair of female
713:
712:
16:(Redirected from
5691:
5537:
5530:
5523:
5514:
5513:
5488:
5486:
5485:
5473:
5471:
5470:
5461:. Archived from
5453:
5451:
5450:
5444:
5429:
5420:
5418:
5417:
5411:
5405:. Archived from
5372:
5362:
5335:
5325:
5315:
5298:(26): 10915–20.
5282:
5280:
5279:
5235:
5217:
5196:
5178:
5153:
5100:
5099:
5091:
5085:
5084:
5076:
5070:
5069:
5039:
5033:
5032:
5030:
5029:
5010:
5004:
4991:
4985:
4984:
4974:
4950:
4944:
4943:
4941:
4939:
4919:
4913:
4912:
4910:
4908:
4888:
4882:
4881:
4844:
4838:
4837:
4835:
4834:
4814:
4808:
4807:
4805:
4803:
4784:
4778:
4777:
4767:
4757:
4733:
4722:
4721:
4719:
4718:
4709:. Archived from
4680:
4674:
4673:
4671:
4670:
4664:
4658:. Archived from
4657:
4649:
4643:
4642:
4632:
4600:
4594:
4593:
4591:
4590:
4568:
4562:
4561:
4551:
4511:
4505:
4504:
4494:
4462:
4456:
4455:
4439:
4433:
4432:
4422:
4390:
4384:
4383:
4381:
4379:
4373:
4362:
4353:
4347:
4346:
4318:
4305:
4304:
4302:
4301:
4282:
4276:
4275:
4273:
4272:
4253:
4247:
4246:
4244:
4243:
4224:
4218:
4217:
4215:
4213:
4199:
4191:
4185:
4184:
4158:
4152:
4151:
4149:
4147:
4133:
4125:
4119:
4107:
4101:
4100:
4064:
4058:
4057:
4047:
4023:
4017:
4016:
4014:
4012:
3997:
3991:
3990:
3988:
3987:
3947:
3941:
3940:
3915:(11): 997–1004.
3904:
3898:
3897:
3895:
3893:
3888:on 27 April 2013
3874:
3868:
3867:
3865:
3863:
3852:.littleindia.com
3844:
3838:
3837:
3835:
3833:
3814:
3808:
3807:
3805:
3804:
3785:
3779:
3778:
3776:
3775:
3760:
3754:
3737:
3731:
3730:
3728:
3726:
3706:
3700:
3699:
3663:
3657:
3656:
3618:
3612:
3611:
3609:
3608:
3602:
3575:
3566:
3560:
3559:
3557:
3556:
3529:
3520:
3507:
3501:
3488:
3479:
3478:
3468:
3444:
3438:
3437:
3418:(5th ed.).
3408:Benirschke, Kurt
3404:
3398:
3397:
3395:
3394:
3378:
3367:
3366:
3350:
3340:
3323:
3322:
3320:
3319:
3313:
3307:. Archived from
3283:(9385): 735–43.
3272:
3266:Hall JG (2003).
3263:
3257:
3256:
3249:
3243:
3240:
3238:
3236:
3199:
3189:
3165:
3159:
3158:
3148:
3108:
3102:
3101:
3056:
3050:
3049:
3047:
3045:
3025:
3019:
3018:
2973:
2967:
2966:
2954:
2948:
2947:
2921:
2915:
2914:
2894:
2884:
2878:
2877:
2867:
2857:
2825:
2819:
2818:
2781:
2775:
2774:
2749:(12): 999–1003.
2738:
2732:
2731:
2703:
2697:
2696:
2686:
2654:
2648:
2647:
2637:
2605:
2599:
2598:
2596:
2595:
2576:
2570:
2569:
2567:
2566:
2534:
2528:
2527:
2521:
2513:
2511:
2510:
2494:
2488:
2487:
2477:
2453:
2447:
2446:
2444:
2443:
2422:
2416:
2415:
2413:
2411:
2400:
2394:
2393:
2375:
2351:
2342:
2341:
2323:
2317:
2316:
2314:
2313:
2298:
2292:
2291:
2289:
2287:
2272:
2266:
2265:
2263:
2262:
2237:
2231:
2230:
2228:
2227:
2202:
2196:
2195:
2167:
2161:
2160:
2153:
2147:
2146:
2144:
2142:
2123:
2117:
2116:
2114:
2113:
2102:Ask a Geneticist
2093:
2087:
2086:
2084:
2083:
2064:
2058:
2057:
2026:
2020:
2019:
2009:
1999:
1963:
1952:
1951:
1949:
1948:
1929:
1923:
1922:
1904:
1898:
1897:
1895:
1894:
1875:
1869:
1868:
1866:
1865:
1846:
1840:
1839:
1837:
1836:
1820:
1812:
1806:
1793:
1787:
1784:
1778:
1777:
1775:
1774:
1759:
1753:
1746:
1740:
1727:
1690:Superfecundation
1613:Vespertilionidae
1569:
1562:
1558:
1555:
1549:
1526:
1525:
1518:
1326:superfecundation
1270:vaginal delivery
1186:Low birth weight
880:Mohammadpur Umri
745:
721:
575:numerical prefix
556:
555:
295:may look similar
21:
5699:
5698:
5694:
5693:
5692:
5690:
5689:
5688:
5659:
5658:
5657:
5652:
5626:
5599:Conjoined twins
5593:
5565:
5547:
5541:
5511:
5483:
5481:
5468:
5466:
5448:
5446:
5442:
5427:
5423:
5415:
5413:
5409:
5370:
5351:
5277:
5275:
5215:10.1.1.378.4082
5109:
5107:Further reading
5104:
5103:
5092:
5088:
5077:
5073:
5040:
5036:
5027:
5025:
5012:
5011:
5007:
5001:Wayback Machine
4992:
4988:
4951:
4947:
4937:
4935:
4920:
4916:
4906:
4904:
4889:
4885:
4845:
4841:
4832:
4830:
4815:
4811:
4801:
4799:
4786:
4785:
4781:
4734:
4725:
4716:
4714:
4699:
4681:
4677:
4668:
4666:
4662:
4655:
4651:
4650:
4646:
4601:
4597:
4588:
4586:
4569:
4565:
4526:(2): CD008313.
4512:
4508:
4463:
4459:
4440:
4436:
4405:(5): 1095–101.
4391:
4387:
4377:
4375:
4371:
4360:
4354:
4350:
4319:
4308:
4299:
4297:
4284:
4283:
4279:
4270:
4268:
4255:
4254:
4250:
4241:
4239:
4226:
4225:
4221:
4211:
4209:
4192:
4188:
4181:
4159:
4155:
4145:
4143:
4126:
4122:
4108:
4104:
4065:
4061:
4024:
4020:
4010:
4008:
3999:
3998:
3994:
3985:
3983:
3948:
3944:
3905:
3901:
3891:
3889:
3882:himsamachar.com
3876:
3875:
3871:
3861:
3859:
3846:
3845:
3841:
3831:
3829:
3816:
3815:
3811:
3802:
3800:
3793:The Independent
3787:
3786:
3782:
3773:
3771:
3762:
3761:
3757:
3748:Wayback Machine
3738:
3734:
3724:
3722:
3707:
3703:
3664:
3660:
3637:
3619:
3615:
3606:
3604:
3600:
3573:
3567:
3563:
3554:
3552:
3530:
3523:
3517:Wayback Machine
3508:
3504:
3498:Wayback Machine
3489:
3482:
3445:
3441:
3434:
3405:
3401:
3392:
3390:
3379:
3370:
3363:
3341:
3326:
3317:
3315:
3311:
3270:
3264:
3260:
3251:
3250:
3246:
3234:
3232:
3166:
3162:
3109:
3105:
3057:
3053:
3043:
3041:
3026:
3022:
2979:Nature Genetics
2974:
2970:
2955:
2951:
2936:
2922:
2918:
2903:
2885:
2881:
2840:(30): 10604–9.
2826:
2822:
2782:
2778:
2739:
2735:
2704:
2700:
2655:
2651:
2606:
2602:
2593:
2591:
2578:
2577:
2573:
2564:
2562:
2549:(11): 913–921.
2535:
2531:
2515:
2514:
2508:
2506:
2495:
2491:
2454:
2450:
2441:
2439:
2424:
2423:
2419:
2409:
2407:
2402:
2401:
2397:
2352:
2345:
2338:
2324:
2320:
2311:
2309:
2300:
2299:
2295:
2285:
2283:
2274:
2273:
2269:
2260:
2258:
2241:"Italy: People"
2239:
2238:
2234:
2225:
2223:
2204:
2203:
2199:
2168:
2164:
2155:
2154:
2150:
2140:
2138:
2125:
2124:
2120:
2111:
2109:
2094:
2090:
2081:
2079:
2066:
2065:
2061:
2027:
2023:
1966:Smits, Jeroen;
1964:
1955:
1946:
1944:
1931:
1930:
1926:
1919:
1905:
1901:
1892:
1890:
1877:
1876:
1872:
1863:
1861:
1848:
1847:
1843:
1834:
1832:
1813:
1809:
1803:Wayback Machine
1794:
1790:
1785:
1781:
1772:
1770:
1765:. Nlm.nih.gov.
1761:
1760:
1756:
1747:
1743:
1737:Wayback Machine
1728:
1724:
1719:
1714:
1665:Litter (animal)
1630:
1570:
1559:
1553:
1550:
1543:
1527:
1523:
1516:
1494:
1481:
1443:Michael Gabbett
1385:
1373:Turner syndrome
1360:
1340:
1334:
1322:
1317:
1288:
1282:
1266:
1251:
1239:
1214:
1208:
1188:
1172:
1170:Miscarried twin
1155:
1143:
1137:
1135:Parasitic twins
1129:Lydia Fairchild
1112:
1106:
1066:
1064:Conjoined twins
1060:
1058:Conjoined twins
1038:
1032:
1030:Vanishing twins
1027:
990:
926:
892:multiple births
809:
803:
795:growth hormones
791:fertility drugs
771:
764:
753:gestational age
746:
737:
722:
707:conjoined twins
689:Conjoined twins
540:conjoined twins
522:
502:without a heart
494:
484:Nature Genetics
395:
380:
372:embryo transfer
349:
315:
214:
169:
121:
87:In contrast, a
39:
28:
23:
22:
18:Fraternal Twins
15:
12:
11:
5:
5697:
5687:
5686:
5681:
5676:
5671:
5654:
5653:
5651:
5650:
5645:
5640:
5638:Vanishing twin
5634:
5632:
5628:
5627:
5625:
5624:
5623:
5622:
5614:
5607:Parasitic twin
5603:
5601:
5595:
5594:
5592:
5591:
5586:
5581:
5575:
5573:
5567:
5566:
5564:
5563:
5557:
5555:
5549:
5548:
5540:
5539:
5532:
5525:
5517:
5510:
5509:External links
5507:
5506:
5505:
5500:
5493:
5489:
5477:Taylor, Ally.
5474:
5454:
5432:TWINS Magazine
5421:
5381:(2): 430–436.
5363:
5349:
5336:
5283:
5251:(3): e447–53.
5236:
5208:(6): 1159–61.
5197:
5154:
5117:
5108:
5105:
5102:
5101:
5086:
5071:
5052:(6): 387–395.
5034:
5020:. 2015-10-01.
5005:
4986:
4945:
4914:
4883:
4850:Human Genetics
4839:
4809:
4779:
4723:
4697:
4675:
4644:
4595:
4563:
4506:
4457:
4434:
4399:Obstet Gynecol
4385:
4348:
4306:
4277:
4248:
4219:
4186:
4179:
4153:
4120:
4102:
4059:
4018:
3992:
3962:(2): 132–136.
3942:
3899:
3869:
3839:
3822:Times of India
3809:
3799:on 15 May 2009
3780:
3755:
3739:Linda Geddes:
3732:
3701:
3674:(4): 431–437.
3658:
3635:
3613:
3561:
3544:(5): 405–410.
3521:
3502:
3480:
3439:
3432:
3399:
3368:
3361:
3324:
3258:
3244:
3242:
3241:
3180:(2): 236–242.
3160:
3123:(6): 533–537.
3103:
3051:
3020:
2968:
2949:
2934:
2916:
2901:
2879:
2820:
2776:
2733:
2714:(3): 216–228.
2698:
2669:(2): 117–123.
2649:
2600:
2571:
2529:
2489:
2462:Fertil. Steril
2448:
2434:. 2007-07-02.
2417:
2395:
2366:(2): 179–187.
2343:
2336:
2318:
2293:
2267:
2253:. 2008-09-04.
2232:
2218:. 2008-09-04.
2197:
2178:(3): 189–202.
2162:
2148:
2118:
2088:
2059:
2037:(4): 599–609.
2021:
1953:
1924:
1917:
1899:
1885:. 2001-06-07.
1870:
1856:. 2007-11-12.
1841:
1807:
1788:
1779:
1754:
1741:
1721:
1720:
1718:
1715:
1713:
1712:
1707:
1702:
1697:
1692:
1687:
1682:
1680:Multiple birth
1677:
1672:
1667:
1662:
1657:
1652:
1647:
1642:
1637:
1631:
1629:
1626:
1572:
1571:
1530:
1528:
1521:
1515:
1512:
1493:
1490:
1486:situs inversus
1480:
1477:
1434:XX, and one a
1384:
1381:
1359:
1356:
1336:Main article:
1333:
1330:
1321:
1318:
1316:
1313:
1284:Main article:
1281:
1278:
1265:
1262:
1250:
1247:
1238:
1235:
1210:Main article:
1207:
1204:
1200:cerebral palsy
1187:
1184:
1180:vanishing twin
1171:
1168:
1154:
1151:
1141:Parasitic twin
1139:Main article:
1136:
1133:
1108:Main article:
1105:
1102:
1062:Main article:
1059:
1056:
1048:vanishing twin
1036:Vanishing twin
1034:Main article:
1031:
1028:
1026:
1023:
1014:
1013:
1010:
1007:
1004:
1001:
989:
986:
954:
953:
950:
947:
944:
925:
922:
888:
887:
877:
867:
805:Main article:
802:
799:
784:growth hormone
770:
767:
766:
765:
761:sagittal plane
747:
740:
738:
730:sagittal plane
723:
716:
711:
710:
703:
691:
685:
684:
681:
677:cerebral palsy
650:
644:
643:
640:
607:
601:
600:
593:
571:
567:
566:
563:
560:
521:
518:
493:
490:
394:
391:
379:
376:
361:zona pellucida
348:
345:
314:
311:
213:
210:
187:
186:
183:
180:
168:
165:
153:Southeast Asia
141:Central Africa
120:
117:
101:multiple birth
26:
9:
6:
4:
3:
2:
5696:
5685:
5682:
5680:
5677:
5675:
5672:
5670:
5667:
5666:
5664:
5649:
5646:
5644:
5641:
5639:
5636:
5635:
5633:
5629:
5621:
5620:
5615:
5613:
5610:
5609:
5608:
5605:
5604:
5602:
5600:
5596:
5590:
5587:
5585:
5582:
5580:
5577:
5576:
5574:
5572:
5568:
5562:
5559:
5558:
5556:
5554:
5550:
5545:
5538:
5533:
5531:
5526:
5524:
5519:
5518:
5515:
5504:
5501:
5498:
5494:
5490:
5480:
5475:
5465:on 2009-10-15
5464:
5460:
5455:
5445:on 2008-10-30
5441:
5437:
5433:
5426:
5422:
5412:on 2008-10-02
5408:
5404:
5400:
5396:
5392:
5388:
5384:
5380:
5376:
5369:
5364:
5360:
5356:
5352:
5346:
5342:
5337:
5333:
5329:
5324:
5319:
5314:
5309:
5305:
5301:
5297:
5293:
5289:
5284:
5274:
5270:
5266:
5262:
5258:
5254:
5250:
5246:
5242:
5237:
5233:
5229:
5225:
5221:
5216:
5211:
5207:
5203:
5198:
5194:
5190:
5186:
5182:
5177:
5172:
5168:
5164:
5160:
5155:
5151:
5147:
5143:
5139:
5135:
5131:
5127:
5123:
5118:
5115:
5112:Bacon, Kate.
5111:
5110:
5097:
5090:
5082:
5075:
5067:
5063:
5059:
5055:
5051:
5047:
5046:
5038:
5023:
5019:
5015:
5009:
5002:
4998:
4995:
4990:
4982:
4978:
4973:
4968:
4964:
4960:
4956:
4949:
4933:
4929:
4925:
4918:
4902:
4898:
4894:
4887:
4879:
4875:
4871:
4867:
4863:
4859:
4856:(2): 179–85.
4855:
4851:
4843:
4828:
4824:
4820:
4813:
4797:
4793:
4789:
4783:
4775:
4771:
4766:
4761:
4756:
4751:
4747:
4743:
4739:
4732:
4730:
4728:
4713:on 2009-01-06
4712:
4708:
4704:
4700:
4694:
4690:
4686:
4679:
4665:on 2016-03-04
4661:
4654:
4648:
4640:
4636:
4631:
4626:
4622:
4618:
4614:
4610:
4606:
4599:
4584:
4580:
4579:
4574:
4567:
4559:
4555:
4550:
4545:
4541:
4537:
4533:
4529:
4525:
4521:
4517:
4510:
4502:
4498:
4493:
4488:
4484:
4480:
4476:
4472:
4468:
4461:
4453:
4449:
4445:
4438:
4430:
4426:
4421:
4416:
4412:
4408:
4404:
4400:
4396:
4389:
4374:on 2011-12-15
4370:
4366:
4359:
4352:
4344:
4340:
4336:
4332:
4329:(2): 209–19.
4328:
4324:
4317:
4315:
4313:
4311:
4295:
4291:
4287:
4281:
4266:
4262:
4258:
4252:
4237:
4233:
4229:
4223:
4207:
4203:
4202:New scientist
4198:
4190:
4182:
4176:
4172:
4168:
4164:
4157:
4141:
4137:
4132:
4124:
4117:
4113:
4106:
4098:
4094:
4090:
4086:
4082:
4078:
4075:(3): 346–53.
4074:
4070:
4063:
4055:
4051:
4046:
4041:
4037:
4033:
4029:
4022:
4006:
4002:
3996:
3981:
3977:
3973:
3969:
3965:
3961:
3957:
3956:Twin Research
3953:
3946:
3938:
3934:
3930:
3926:
3922:
3918:
3914:
3910:
3903:
3887:
3883:
3879:
3873:
3857:
3853:
3849:
3843:
3827:
3823:
3819:
3813:
3798:
3794:
3790:
3784:
3769:
3765:
3759:
3752:
3751:New Scientist
3749:
3745:
3742:
3736:
3720:
3716:
3715:The Telegraph
3712:
3705:
3697:
3693:
3689:
3685:
3681:
3677:
3673:
3669:
3662:
3654:
3650:
3646:
3642:
3638:
3632:
3628:
3624:
3617:
3599:
3595:
3591:
3587:
3583:
3579:
3572:
3565:
3551:
3547:
3543:
3539:
3535:
3528:
3526:
3518:
3514:
3511:
3506:
3499:
3495:
3492:
3487:
3485:
3476:
3472:
3467:
3462:
3459:(12): 753–8.
3458:
3454:
3450:
3443:
3435:
3429:
3425:
3421:
3417:
3413:
3409:
3403:
3388:
3384:
3377:
3375:
3373:
3364:
3358:
3354:
3349:
3348:
3339:
3337:
3335:
3333:
3331:
3329:
3314:on 2016-06-03
3310:
3306:
3302:
3298:
3294:
3290:
3286:
3282:
3278:
3277:
3269:
3262:
3254:
3248:
3230:
3226:
3222:
3218:
3214:
3210:
3206:
3201:
3200:
3197:
3193:
3188:
3183:
3179:
3175:
3171:
3164:
3156:
3152:
3147:
3142:
3138:
3134:
3130:
3126:
3122:
3118:
3114:
3107:
3099:
3095:
3091:
3087:
3083:
3079:
3075:
3071:
3067:
3063:
3055:
3039:
3035:
3031:
3024:
3016:
3012:
3008:
3004:
3000:
2996:
2992:
2988:
2984:
2980:
2972:
2964:
2960:
2953:
2945:
2941:
2937:
2931:
2927:
2920:
2912:
2908:
2904:
2902:0-525-94465-6
2898:
2893:
2892:
2883:
2875:
2871:
2866:
2861:
2856:
2851:
2847:
2843:
2839:
2835:
2831:
2824:
2816:
2812:
2808:
2804:
2800:
2796:
2792:
2788:
2787:J. Med. Genet
2780:
2772:
2768:
2764:
2760:
2756:
2752:
2748:
2744:
2737:
2729:
2725:
2721:
2717:
2713:
2709:
2702:
2694:
2690:
2685:
2680:
2676:
2672:
2668:
2664:
2660:
2653:
2645:
2641:
2636:
2631:
2627:
2623:
2620:(3): 234–43.
2619:
2615:
2611:
2604:
2590:on 2007-09-21
2589:
2585:
2581:
2575:
2560:
2556:
2552:
2548:
2544:
2540:
2533:
2525:
2519:
2504:
2500:
2493:
2485:
2481:
2476:
2471:
2467:
2463:
2459:
2452:
2437:
2433:
2432:
2427:
2421:
2405:
2399:
2391:
2387:
2383:
2379:
2374:
2369:
2365:
2361:
2357:
2350:
2348:
2339:
2333:
2329:
2322:
2308:on 2016-03-04
2307:
2303:
2297:
2281:
2277:
2271:
2256:
2252:
2248:
2247:
2242:
2236:
2221:
2217:
2213:
2212:
2207:
2201:
2193:
2189:
2185:
2181:
2177:
2173:
2166:
2158:
2152:
2136:
2132:
2128:
2122:
2107:
2103:
2099:
2092:
2077:
2073:
2072:Go Ask Alice!
2069:
2063:
2056:
2052:
2048:
2044:
2040:
2036:
2032:
2025:
2017:
2013:
2008:
2003:
1998:
1993:
1989:
1985:
1982:(9): e25239.
1981:
1977:
1973:
1969:
1962:
1960:
1958:
1942:
1938:
1934:
1928:
1920:
1914:
1910:
1903:
1888:
1884:
1880:
1874:
1859:
1855:
1851:
1845:
1830:
1826:
1825:
1819:
1811:
1804:
1800:
1797:
1792:
1783:
1768:
1764:
1758:
1751:
1745:
1738:
1734:
1731:
1726:
1722:
1711:
1708:
1706:
1703:
1701:
1698:
1696:
1693:
1691:
1688:
1686:
1683:
1681:
1678:
1676:
1673:
1671:
1668:
1666:
1663:
1661:
1658:
1656:
1653:
1651:
1648:
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1638:
1636:
1633:
1632:
1625:
1621:
1618:
1614:
1608:
1604:
1602:
1598:
1597:DNA profiling
1593:
1589:
1584:
1580:
1568:
1565:
1557:
1547:
1541:
1540:
1536:
1531:This section
1529:
1520:
1519:
1511:
1508:
1504:
1499:
1489:
1487:
1476:
1474:
1472:
1468:
1464:
1460:
1459:heterogonesis
1456:
1452:
1448:
1447:Nicholas Fisk
1444:
1439:
1437:
1433:
1430:. One was an
1429:
1421:
1417:
1412:
1408:
1406:
1402:
1401:heterogonesis
1398:
1394:
1389:
1380:
1378:
1374:
1368:
1366:
1355:
1353:
1349:
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1339:
1329:
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1312:
1310:
1306:
1305:environmental
1302:
1301:psychological
1298:
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918:
916:
912:
908:
903:
901:
897:
893:
885:
884:Uttar Pradesh
882:, located in
881:
878:
875:
872:, located in
871:
868:
866:
862:
859:
858:
857:
854:
853:Josef Mengele
850:
846:
845:Cândido Godói
842:
838:
837:ethnic groups
834:
826:
825:Yoruba people
822:
818:
813:
808:
798:
796:
792:
787:
785:
780:
776:
762:
758:
757:coronal plane
754:
750:
744:
739:
735:
734:coronal plane
731:
727:
726:co-incubation
720:
715:
714:
708:
704:
702:
699:
697:
692:
690:
687:
686:
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664:
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655:
651:
649:
646:
645:
641:
639:
637:
633:
628:
626:
622:
621:almost always
618:
617:amniotic sacs
612:
608:
606:
603:
602:
598:
597:fertilisation
594:
592:
588:
584:
583:amniotic sacs
580:
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569:
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541:
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429:
425:
420:
417:
408:
407:amniotic sacs
404:
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369:
364:
362:
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344:
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176:
173:
164:
162:
156:
154:
150:
146:
145:South America
142:
138:
134:
133:phytoestrogen
130:
126:
125:Yoruba people
116:
114:
110:
106:
102:
98:
94:
90:
85:
83:
79:
75:
71:
67:
63:
59:
55:
48:
43:
37:
33:
19:
5618:
5560:
5543:
5482:. Retrieved
5467:. Retrieved
5463:the original
5447:. Retrieved
5440:the original
5431:
5414:. Retrieved
5407:the original
5378:
5374:
5340:
5295:
5291:
5276:. Retrieved
5248:
5244:
5205:
5201:
5166:
5162:
5125:
5121:
5113:
5095:
5089:
5080:
5074:
5049:
5043:
5037:
5026:. Retrieved
5017:
5008:
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4958:
4948:
4936:. Retrieved
4932:the original
4917:
4905:. Retrieved
4901:the original
4896:
4886:
4853:
4849:
4842:
4831:. Retrieved
4822:
4812:
4800:. Retrieved
4791:
4782:
4765:10072/384437
4745:
4741:
4715:. Retrieved
4711:the original
4688:
4678:
4667:. Retrieved
4660:the original
4647:
4615:(1): 64–68.
4612:
4608:
4598:
4587:. Retrieved
4578:The Guardian
4576:
4566:
4523:
4519:
4509:
4474:
4470:
4460:
4447:
4437:
4402:
4398:
4388:
4376:. Retrieved
4369:the original
4364:
4351:
4326:
4322:
4298:. Retrieved
4289:
4280:
4269:. Retrieved
4260:
4251:
4240:. Retrieved
4231:
4222:
4212:17 September
4210:. Retrieved
4201:
4189:
4162:
4156:
4144:. Retrieved
4135:
4123:
4105:
4072:
4068:
4062:
4035:
4031:
4021:
4009:. Retrieved
4004:
3995:
3984:. Retrieved
3959:
3955:
3945:
3912:
3908:
3902:
3890:. Retrieved
3886:the original
3881:
3872:
3860:. Retrieved
3856:the original
3851:
3842:
3830:. Retrieved
3821:
3812:
3801:. Retrieved
3797:the original
3792:
3783:
3772:. Retrieved
3758:
3735:
3723:. Retrieved
3714:
3704:
3671:
3667:
3661:
3622:
3616:
3605:. Retrieved
3581:
3577:
3564:
3553:. Retrieved
3541:
3538:J Reprod Med
3537:
3505:
3456:
3452:
3442:
3420:Philadelphia
3415:
3402:
3391:. Retrieved
3346:
3316:. Retrieved
3309:the original
3280:
3274:
3261:
3247:
3233:. Retrieved
3208:
3177:
3173:
3163:
3120:
3116:
3106:
3065:
3061:
3054:
3042:. Retrieved
3033:
3023:
2985:(1): 27–34.
2982:
2978:
2971:
2962:
2958:
2952:
2925:
2919:
2890:
2882:
2837:
2833:
2823:
2793:(1): 28–34.
2790:
2786:
2779:
2746:
2743:Prenat Diagn
2742:
2736:
2711:
2707:
2701:
2666:
2662:
2652:
2617:
2613:
2603:
2592:. Retrieved
2588:the original
2574:
2563:. Retrieved
2546:
2542:
2532:
2507:. Retrieved
2502:
2492:
2468:(2): 423–7.
2465:
2461:
2451:
2440:. Retrieved
2429:
2420:
2408:. Retrieved
2398:
2363:
2359:
2327:
2321:
2310:. Retrieved
2306:the original
2296:
2284:. Retrieved
2270:
2259:. Retrieved
2244:
2235:
2224:. Retrieved
2209:
2200:
2175:
2171:
2165:
2151:
2139:. Retrieved
2130:
2121:
2110:. Retrieved
2101:
2091:
2080:. Retrieved
2071:
2062:
2054:
2034:
2030:
2024:
1979:
1975:
1945:. Retrieved
1936:
1927:
1908:
1902:
1891:. Retrieved
1873:
1862:. Retrieved
1853:
1844:
1833:. Retrieved
1822:
1810:
1791:
1782:
1771:. Retrieved
1757:
1749:
1744:
1725:
1710:Virtual twin
1640:Doppelgänger
1622:
1609:
1605:
1575:
1560:
1551:
1544:Please help
1539:verification
1532:
1503:cryptophasia
1495:
1482:
1475:
1440:
1424:
1386:
1369:
1364:
1361:
1341:
1323:
1309:human nature
1289:
1267:
1252:
1240:
1231:polycythemic
1223:
1192:birth weight
1189:
1173:
1156:
1144:
1113:
1082:
1039:
1019:
1015:
991:
981:
963:
955:
937:West African
930:
927:
919:
904:
899:
889:
832:
830:
788:
772:
769:Demographics
700:
693:
670:
667:
659:
657:
629:
627:have fused.
620:
614:
590:
562:Description
548:
537:
533:
523:
511:
495:
482:
476:
464:
440:
421:
416:fingerprints
412:
388:
384:
381:
365:
352:
350:
328:
325:
321:
317:
316:
307:
299:
280:
267:
263:
255:
243:
240:
236:
232:
231:
200:
195:
191:
188:
174:
170:
157:
122:
113:doppelgänger
107:. Unrelated
104:
96:
86:
77:
65:
53:
52:
5648:Mixed twins
5169:(1): 43–7.
5128:(1): 72–6.
4965:(1): 81–5.
4938:28 February
4907:28 February
4802:28 February
4169:. pp.
3453:J Perinatol
2503:WonderQuest
2431:EurekAlert!
2141:11 November
2131:China Daily
1675:Mixed twins
1507:Idioglossia
1388:Monozygotic
1348:mixed twins
1338:Mixed twins
1332:Mixed twins
1242:Stillbirths
1237:Stillbirths
1176:miscarriage
974:anovulation
900:monozygotic
663:monozygotic
625:blastocysts
587:monozygotic
500:twin fetus
459:Scott Kelly
318:Monozygotic
258:, form two
252:sperm cells
109:look-alikes
66:monozygotic
5663:Categories
5546:conditions
5484:2018-03-30
5469:2008-10-18
5449:2008-10-06
5416:2008-10-02
5278:2008-10-06
5245:Pediatrics
5028:2018-09-05
4833:2023-04-29
4717:2008-09-30
4669:2015-04-18
4589:2012-04-07
4300:2015-10-26
4290:BabyCentre
4271:2015-10-23
4242:2015-10-23
3986:2013-08-10
3892:23 October
3862:23 October
3832:23 October
3803:2009-08-06
3774:2009-08-06
3607:2008-09-29
3555:2008-09-29
3393:2008-10-10
3383:"Twinning"
3318:2016-05-03
3276:The Lancet
3268:"Twinning"
3235:7 February
2965:: 147–159.
2594:2008-09-30
2565:2008-10-02
2509:2007-03-22
2442:2019-08-05
2312:2013-09-16
2261:2008-10-02
2226:2008-10-02
2112:2022-04-07
2082:2022-04-07
1947:2022-04-07
1893:2008-09-29
1864:2008-09-29
1835:2008-09-29
1773:2016-06-16
1717:References
1695:Twin study
1685:Multiverse
1670:Look-alike
1554:March 2024
1377:karyotypes
1286:Twin study
935:She is of
506:polar body
471:epigenetic
432:phenotypes
428:aneuploidy
357:blastocyst
248:fertilized
208:of twins.
149:South Asia
119:Statistics
5643:Chimerism
5375:Evolution
5359:123390922
5210:CiteSeerX
4707:172964621
4540:1469-493X
4477:: i4353.
4136:The Times
3645:1358-8702
3305:208792233
3137:1058-0468
3044:8 January
3015:230986741
2999:1546-1718
2382:1355-4786
1645:Evil twin
1583:ovulation
1535:citations
1418:breed in
1196:premature
1160:triploidy
1125:DNA tests
1117:mosaicism
1104:Chimerism
978:clomifene
833:dizygotic
817:ere ibeji
801:Ethnicity
797:in food.
642:Days 4-8
577:for two)
551:placentas
514:triploidy
378:Incidence
347:Mechanism
326:identical
264:dizygotic
241:fraternal
233:Dizygotic
97:singleton
78:dizygotic
62:pregnancy
58:offspring
5553:Zygosity
5395:15068359
5332:17576931
5273:20498737
5265:17766488
5193:23507167
5150:19112883
5142:10073913
5066:16690234
5022:Archived
4997:Archived
4870:17165045
4827:Archived
4796:Archived
4792:CBC News
4774:30811910
4583:Archived
4558:27075527
4501:27599496
4452:Archived
4448:BBC News
4429:22015878
4343:23062593
4294:Archived
4265:Archived
4236:Archived
4206:Archived
4140:Archived
4097:19195460
4089:18307076
4054:24304051
3980:Archived
3976:11931691
3937:45092501
3826:Archived
3768:Archived
3744:Archived
3719:Archived
3696:23862192
3653:36287045
3598:Archived
3594:11968567
3588:: 1–17.
3550:16779988
3513:Archived
3494:Archived
3475:16281049
3410:(2004).
3387:Archived
3297:12957099
3229:Archived
3225:85215225
3196:12571155
3155:22460080
3038:Archived
3007:33414551
2944:43894450
2911:40396458
2874:16009939
2807:24123875
2771:31844710
2763:11113914
2644:18669930
2559:Archived
2555:10589400
2518:cite web
2484:19217091
2436:Archived
2390:10336022
2280:Archived
2255:Archived
2220:Archived
2135:Archived
2106:Archived
2076:Archived
2051:18063108
2016:21980404
1976:PLOS ONE
1941:Archived
1939:. 1999.
1887:Archived
1858:Archived
1829:Archived
1799:Archived
1767:Archived
1733:Archived
1628:See also
1432:intersex
1428:chimeras
1416:Hereford
1365:in utero
1344:biracial
1147:parasite
1121:intersex
1077:Thailand
1052:chimeric
861:Igbo-Ora
632:placenta
611:placenta
579:chorions
424:genotype
403:placenta
291:siblings
272:siblings
268:biovular
202:Zygosity
196:in utero
192:in utero
105:multiple
56:are two
5684:Zoology
5679:Sibling
5619:in fetu
5403:9460009
5323:1904168
5300:Bibcode
5232:9176461
5185:1488855
4981:6540028
4928:Gannett
4897:Reuters
4878:3343267
4823:YouTube
4630:1013354
4549:6464533
4492:5013231
4420:3202294
4378:12 June
3929:7437372
3725:5 April
3688:9181177
3627:Informa
3146:3370038
3098:7196086
3090:1686613
3070:Bibcode
3062:Science
2865:1174919
2842:Bibcode
2815:6031153
2728:8741866
2693:6007033
2684:1012913
2635:2586810
2286:24 July
2192:6805197
2007:3182188
1984:Bibcode
1635:Cloning
1617:Cebidae
1514:Animals
1297:genetic
1293:medical
915:malaria
911:Nigeria
886:, India
876:, India
870:Kodinhi
865:Nigeria
851:doctor
479:Iceland
353:natural
341:embryos
287:meiosis
285:during
260:zygotes
161:ovulate
137:ovaries
74:embryos
5617:Fetus
5401:
5393:
5357:
5347:
5330:
5320:
5271:
5263:
5230:
5212:
5191:
5183:
5148:
5140:
5064:
4979:
4876:
4868:
4772:
4705:
4695:
4639:944787
4637:
4627:
4556:
4546:
4538:
4499:
4489:
4427:
4417:
4341:
4177:
4146:9 July
4095:
4087:
4052:
4011:9 July
3974:
3935:
3927:
3694:
3686:
3651:
3643:
3633:
3592:
3584:(24).
3548:
3473:
3430:
3359:
3303:
3295:
3223:
3209:Nature
3194:
3153:
3143:
3135:
3096:
3088:
3013:
3005:
2997:
2942:
2932:
2909:
2899:
2872:
2862:
2813:
2805:
2769:
2761:
2726:
2691:
2681:
2642:
2632:
2553:
2482:
2410:9 July
2388:
2380:
2334:
2190:
2049:
2014:
2004:
1915:
1588:allele
1579:litter
1471:morula
1405:morula
1352:London
1227:anemic
982:Clomid
941:Yoruba
874:Kerala
841:Yoruba
823:. The
696:zygote
660:always
654:amnion
337:zygote
206:genome
151:, and
70:zygote
5631:Other
5443:(PDF)
5428:(PDF)
5410:(PDF)
5399:S2CID
5371:(PDF)
5269:S2CID
5189:S2CID
5146:S2CID
5083:: 24.
4874:S2CID
4663:(PDF)
4656:(PDF)
4372:(PDF)
4361:(PDF)
4232:WebMD
4093:S2CID
3933:S2CID
3692:S2CID
3601:(PDF)
3574:(PDF)
3424:55–62
3312:(PDF)
3301:S2CID
3271:(PDF)
3221:S2CID
3086:JSTOR
3011:S2CID
2811:S2CID
2767:S2CID
1824:WebMD
1451:sperm
1397:sperm
1299:, or
1098:lungs
1094:liver
1090:heart
1086:brain
994:Hesse
976:with
907:Hausa
779:vegan
559:Type
329:twins
324:) or
276:sperm
244:twins
239:) or
103:is a
89:fetus
76:, or
54:Twins
5669:Twin
5561:Twin
5544:Twin
5391:PMID
5355:OCLC
5345:ISBN
5328:PMID
5261:PMID
5228:PMID
5181:PMID
5138:PMID
5062:PMID
4977:PMID
4940:2019
4909:2019
4866:PMID
4804:2019
4770:PMID
4703:OCLC
4693:ISBN
4635:PMID
4554:PMID
4536:ISSN
4497:PMID
4425:PMID
4380:2014
4365:NICE
4339:PMID
4214:2017
4175:ISBN
4148:2021
4085:PMID
4050:PMID
4013:2021
3972:PMID
3925:PMID
3894:2014
3864:2014
3834:2014
3727:2018
3684:PMID
3649:OCLC
3641:ISSN
3631:ISBN
3590:PMID
3546:PMID
3471:PMID
3428:ISBN
3357:ISBN
3293:PMID
3237:2022
3192:PMID
3151:PMID
3133:ISSN
3094:PMID
3046:2021
3003:PMID
2995:ISSN
2940:OCLC
2930:ISBN
2907:OCLC
2897:ISBN
2870:PMID
2803:PMID
2759:PMID
2724:PMID
2689:PMID
2640:PMID
2551:PMID
2524:link
2480:PMID
2412:2023
2386:PMID
2378:ISSN
2332:ISBN
2288:2018
2188:PMID
2143:2008
2047:PMID
2012:PMID
1913:ISBN
1615:and
1537:for
1455:ovum
1445:and
1393:ovum
849:Nazi
581:and
565:Day
457:and
455:Mark
303:ovum
266:and
93:womb
34:and
5492:AH.
5383:doi
5318:PMC
5308:doi
5296:104
5253:doi
5249:120
5220:doi
5171:doi
5130:doi
5054:doi
4967:doi
4858:doi
4854:212
4760:hdl
4750:doi
4746:380
4625:PMC
4617:doi
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