Can You Tell Mary-Kate from Ashley? Take Our Quiz and Prove It.
Slate's Culture Blog Aug. 24 2011 6:11 PM  Can You Tell Mary-
Kate from Ashley?  As part of Slates twins issue this week,
Barry Harbaugh writes about DNA tests that twins can take to
determine whether they are fraternal or identical siblings. He
found that most twins who believe they’re fraternal aren't wrong
about being dizygotic—it’s the identical twins who are more
likely to be mistaken about their twinly identity. When
multiples can describe themselves as being "like two peas in a
pod," he writes, they almost always end up having come from the
same fertilized egg.  That got us thinking about the most famous
twins in the United States: Mary-Kate and Ashley Olsen. Despite
the fact that they look eerily similar—similar enough to have
found fame playing a single character—the pair has always
claimed, without citing scientific evidence, that they are, in
fact, fraternal twins. ("We were just told by the doctors" that
the girls were fraternal, says