Are twins hereditary?

If you suspect a genetic link, you are partially right, but the link is quite complex. For one, genes may play a role in your chance of having fraternal twins (called dizygotic twins) but not identical twins (monozygotic twins). read more

The important difference between identical and fraternal twins is the number of fertilized eggs involved. Identical twins come from a single fertilized egg. Fraternal twins come from two different ones. Identical twins happen when a single embryo splits in two soon after fertilization. This is why identical twins have identical DNA. read more

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