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 ...

Identical twins who were raised apart may have IQ differences similar to those of total strangers, according to new research. The findings suggest that variations in IQ may be less about genetics and ...

Real talk: Plenty of devoted, detail-obsessed parents mix up their own twins sometimes. It's hard to avoid when there are two cute babies in matching onesies rolling around on the same play mat. But ...