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

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 ...

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

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

Usually when you have twins, how you get pregnant with them typically falls under one of two categories: fraternal twins (dizygotic twinning) and identical (monozygotic twinning). You have ...

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 ...