Is having twins genetic?

The likelihood of conceiving twins is a complex trait. It is probably affected by multiple genetic and environmental factors, depending on the type of twins. The two types of twins are classified as monozygotic and dizygotic. Monozygotic (MZ) twins, also called identical twins, occur when a single egg cell is fertilized by a single sperm cell. read more

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! However, for a given pregnancy, only the mother’s genetics matter. Fraternal twins happen when two eggs are simultaneously fertilized instead of just one. read more

For one, genes may play a role in your chance of having fraternal twins (called dizygotic twins) but not identical twins (monozygotic twins). Secondly, it's important to understand that there may be other factors besides genes that increase a woman's chance of having twins. read more

It is probably affected by multiple genetic and environmental factors, depending on the type of twins. The two types of twins are classified as monozygotic and dizygotic. Monozygotic (MZ) twins, also called identical twins, occur when a single egg cell is fertilized by a single sperm cell. read more

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! However, for a given pregnancy, only the mother’s genetics matter. read more

Read whether a family history influences your chance of having twins and if this genetic link exists for both fraternal and identical twins. read more