Around 1 in 250 pregnancies result in identical or “monozygotic” twins, but the mechanism behind monozygotic twinning has remained elusive, partly because the phenomenon is so rare and partly due to ...

Fascination with twins and what twin studies tell us about human nature is universal. There is no question that behavioral and medical science advances have happened largely because twins yield a ...

From Romulus and Remus—the myth of the twin brothers who founded the city of Rome—to the synchronized speech of Australia's "Twinnies" Paula and Brigette Powers, identical siblings have long inspired ...

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 ...

Twins are pretty rare, accounting for just 3% of births in the U.S. these days. But new research shows that for primates 60 million years ago, giving birth to twins was the norm. When you purchase ...

Former conjoined twins are competing in a state cheerleading competition in Texas, almost ten years after being separated in a 12-hour surgery.