are twins more likely to be the same gender?
314332
This differs from fraternal twins, where two eggs (ova) are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times. Twins are more or less equally likely to be female or male.
883917
Identical (monozygotic) twins are always of the same sex because they form from a single zygote (fertilized egg) that contains either male (XY) or female (XX) sex chromosomes. ... Two boy twins: Can be either identical or fraternal (monozygotic or dizygotic)
1425648
Fraternal twins can be either two girls, two boys, or one of each. These are the possible sex combinations: A set of boy/girl twins: Can only be fraternal (dizygotic), as boy/girl twins cannot be identical (monozygotic)
961329
Monozygotic twins are genetically nearly identical and they are always the same sex unless there has been a mutation during development.
270072
All pregnant women have the same chance of having identical twins: about 1 in 250. Identical twins do not run in families. ... older mothers are more likely to have non-identical twins because they're more likely to release more than 1 egg during ovulation.
352434
Identical, or monozygotic, twins may or may not share the same amniotic sac, depending on how early the single fertilized egg divides into 2. If twins are a boy and a girl, clearly they are fraternal twins, as they do not have the same DNA.
71751
In a striking 18 percent of identical twins, products of the same egg with exactly the same genetic makeup, one twin is right-handed and the other left-handed. There also seems to be a higher proportion of fraternal twins with different handedness than is the case with other siblings.
287134
Having identical twins is not genetic. On the other hand, fraternal twins can run in families. Genetics can definitely play a role in having fraternal twins. For example, a woman that has a sibling that is a fraternal twin is 2.5 times more likely to have twins than average!
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Fraternal twins Because they come from different eggs and sperm, they only share about 50 percent of their chromosomes like any other siblings. This means they can be the same or different sexes and aren't identical.
301032
Fraternal twins may be the same gender, they may have many of the same characteristics, but also may be very different from each other and, in fact, share half of their genes just like their sisters and brothers.
548438
However most identical twins grow up together and not only share the same genetics, but also the some environmental influences. ... My twin sister and I have almost always weighed the same or very, very close to the same.
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Do identical twins always have the same hand preference? No! In about 21% of identical (monozygotic or MZ) twin pairs, one twin is right-handed and the other is either left-handed or ambidextrous. Since identical twins share identical genes, this is evidence that handedness is not a totally genetic trait.
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Among monozygotic twins, in extremely rare cases, twins have been born with different sexes (one male, one female). ... 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.
72754
It is common to have a fraternal twin set with one of each gender as opposed to the same gender. For example, in 100 births there will be at least 2 fraternal twins making them more common than identical twins.
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It all started when two sperm fertilized an egg at the exact same time. Twins can be fraternal, identical — and in extremely rare cases — semi-identical. ... Because identical twins share all of their genes, they can't be of opposite sexes like fraternal twins can.
1103130
If twins are a boy and a girl, clearly they are fraternal twins, as they do not have the same DNA. A boy has XY chromosomes and a girl has XX chromosomes. Girl-boy twins occur when one X egg is fertilized with an X sperm, and a Y sperm fertilizes the other X egg.
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Either of a pair of twins who, as a result of developing from a single fertilized ovum, are alike in all genetic characteristics (including sex) and typically very similar in appearance. ... Identical twins have the same? Blood group and sex.