Attendees at a high school graduation on New York's Long Island were left seeing double when 15 sets of twins walked across ...

Many of the students in the tight-knit group have known each other since kindergarten. Some even plan family vacations ...

About 23 in every 1000 births are fraternal, a much higher rate than the three or four out of 1000 births for identical twins. Examining each twin’s DNA will reveal whether they are identical or ...

A graduation ceremony at a Long Island high school this weekend is shaping up to be a double-take affair, with 15 sets of ...

As it turns out, some types of twins are hereditary. Suppose you're pregnant and a close relative (like a parent or sibling) has fraternal (non-identical) twins. In that case, you're twice as ...