Around 1 in 250 pregnancies result in identical or “monozygotic” twins, but the mechanism behind monozygotic twinning has remained elusive, partly because the phenomenon is so rare and partly due to ...

It makes sense that identical twins would have the exact same DNA, right? Spoiler alert: Not always! Here's why. Identical twins (also called monozygotic or MZ twins) are conceived when a single sperm ...

Identical, or monozygotic, twins develop from the same fertilized egg that splits into two. These twins are the same sex and share the same genes. Sometimes called paternal twins, identical twins ...

Mono-mono twins are an incredibly rare type of identical twins who share both a placenta and an amniotic sac. While this makes for a high-risk pregnancy, advances in monitoring and treatment have ...

A mother of twins was left "shocked" after a DNA test involving her two young sons confirmed a long-held suspicion. Charlotte Hassan, 33, admits she was a "little nervous" when she first learned she ...