Contrary to popular belief, Mary-Kate and Ashley Olsen are not identical twins. Yes, you read that right. Despite playing one character, Michelle Tanner, in "Full House" so seamlessly, the Olsen twins are actually fraternal twins, according to their appearance on the "The Late Show with David Letterman." Being fraternal means they originated from separate fertilized eggs and do not share identical DNA. Fraternal twins also don't share as many physical characteristics as identical twins do, but Mary-Kate and Ashley looked so much alike when they were kids that the producers of "Full House" got away with crediting them as a single person until Season 8, according to Screen Rant. Nonetheless, there were subtle differences between the sisters even then.
One notable contrast is their dominant hand — Mary-Kate is left-handed, while Ashley favors her right hand, as Us Weekly noted. Discrepancies in height are also apparent, with Ashley standing an inch taller than Mary-Kate, as the duo shared in an interview with Oprah in 2004. Moreover, a faint freckle above Ashley's upper lip served as a distinguishing feature when they were younger, although it conveniently faded away over time.
As the Olsen twins have matured, the physical disparities between them have become more apparent. Ashley has larger, rounded eyes and fuller lips, while Mary-Kate has a slimmer face with more pronounced cheekbones.
