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 ...

Twin estrangement starts with unresolved anger between twins in childhood. Perhaps one twin is favored over the other twin for parental personal reasons. Another explanation is that one twin is in ...

It's a frequent misconception that identical twins share fingerprints. Each twin has a unique set of fingerprints that convey a different tale, despite the fact that they may appear remarkably alike ...

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 ...

The Science of Siblings is a new series exploring the ways our siblings can influence us, from our money and our mental health all the way down to our very molecules. We'll be sharing these stories ...