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 ...

Conjoined twins—the rare identical twins who fail to separate completely--represent a form of human life that should be respected. There are many variations on typical human development of which we ...