So, having identical twins is not due to genetics. On the other hand, fraternal twins can run in families. In fact, a woman that has a sibling that is a fraternal twin is 2.5 times more likely to have twins than average!

Which parent determines identical twins?

This is why fraternal twins run in families. However, only women ovulate. So, the mothers genes control this and the fathers dont. This is why having a background of twins in the family matters only if it is on the mothers side.

Who carries the identical twin gene?

While men can carry the gene and pass it on to their daughters, a family history of twins doesnt make them any more likely to have twins themselves. 3 But, if a father passes on the twin gene to his daughter, then she may have a higher chance than normal of having fraternal twins.

What causes identical twins?

Identical (monozygotic) twins happen when a single egg (zygote) is fertilised. The egg then divides in 2, creating identical twins who share the same genes. Identical twins are always the same sex, so if your twins are identical, youll have 2 girls or 2 boys.

Do identical twins skip a generation?

When both eggs are fertilized, the resulting siblings are fraternal twins. Because there is no known gene that influences this process, it is considered a mere coincidence when one extended family has multiple sets of identical twins. The notion that twins always skip a generation is also a myth.

Who is most likely to have twins?

According to the Office on Womens Health, women who are aged 30 years or older are more likely to conceive twins. The reason for this is that women of this age are more likely than younger women to release more than one egg during their reproductive cycle.

Can you have twins if it runs in the fathers family?

Heredity on the fathers side does not increase a couples odds of having multiples. This is true even if his family is full of multiples. Men, of course, dont ovulate, so even if theyve inherited that hyperovulation gene from their parents, it doesnt increase their own odds of conceiving twins.

What are my chances of having twins if my mom is a twin?

If a womans mother has fraternal twins, she is about 2 times more likely to have twins. This is why we often say the “risk” for having twins comes from the mother. It doesnt matter if the dad also has fraternal twins in his family – his DNA wont influence how many eggs the mom releases!

What is the rarest type of twin?

Monoamniotic-monochorionic Twins Monoamniotic-monochorionic Twins This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords.