After more than 50 years of research, scientists still don't know exactly what causes autism. But the data make clear that ...

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 ...

Gabrielle Taylor tells PEOPLE that the early fear, physical toll and chaotic newborn phase of having identical twins ...

Hanna and Rebecca Lawrence were happy children who shared the kind of bond twins do, but the 8-year-old girls from Dallas were also different from each other. Hanna was the one with endless energy who ...

Identical twins Sanumi and Sanuthi Ranasinghe have achieved a rare milestone, graduating as medical doctors from the ...

Teenagers who are unhappy with their bodies are more likely to develop symptoms of eating disorders and depression in early ...

Twins easily communicate with each other, which has good and bad consequences. Parental favoritism can create competition, ...

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 ...

For more than a century, scientists have debated whether intelligence is mostly a product of nature or nurture. Identical twins—those born with the same genetic blueprint—have long been the perfect ...

We've seen our fair share of celebrity lookalikes doing the rounds on the web. But some stars don't need to be part of the doppelganger debate because they already have a twin. From identical sets who ...