The similarities may be uncanny, but identical twins aren't exact copies of one another ...

Metastable epialleles may sound like complex science, but they help explain why identical animals can still look and act differently. For years, scientists asked why two mice with identical DNA could ...

If you’re newly pregnant with twins, you may already be wondering if you’ll be welcoming two boys, two girls, or one of each into your family in a few months' time. But what about if you're having ...

When I was a child one of my favorite books was about a pair of identical twins who decided to switch clothes. They looked so much alike that their parents had had to dress one in blue and the other ...

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 ...

Conjoined twins are one of the rarest and most medically remarkable phenomena in human biology. Born physically connected to ...