A twin pregnancy is when there are two fetuses in the uterus at the same time. Twins can be identical, meaning they developed when a single fertilized egg split early in development, or fraternal, ...

This article originally appeared on health. In the middle of all the headline-grabbing political news, Beyoncé stole everyone’s attention by announcing she’s pregnant—with twins! The performer posted ...

Mono-mono twins are an incredibly rare type of identical twins who share both a placenta and an amniotic sac. While this ...

Carrying a twin pregnancy is not an uncommon event. It occurs when the uterus carries two fetuses simultaneously rather than one. Having twins runs in some families and age also appears to be a ...

New reproductive technologies have yielded a vast array of novel variations on the two conventional twin types—identical and fraternal—as well as some curious twin-like sibships. When a Canadian ...