Twins are relatively uncommon and often fascinate people. One set of twin sisters have caused a stir after disclosing a difference in their appearance that's only noticeable in the summer ...

While many people think of twins as a rare "double blessing" decided purely by luck, science suggests that your biological ...

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 ...