Entrepreneurs Tyler and Cameron Winklevoss

(Photo credit should read THOMAS SAMSON/AFP/Getty Images)

Actors Dylan And Cole Sprouse

(Photo by Tim Whitby/Getty Images)

Olympic Gold Medalist Paul Hamm and Olympic Silver Medalist Morgan Hamm

(Photo by Peter Kramer/Getty Images)

Actresses Cynthia and Brittany Daniel

(Photo by Stephen Shugerman/Getty Images)

Singer Aaron Carter and twin sister Angel Carter

(Photo by Kevin Winter/Getty Images)

Actors Daniel and Jon Heder

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Actresses Tamera and Tia Mowry

(Photo by Frazer Harrison/Getty Images)

Sean 'Diddy' Combs and Kim Porter with their twin daughters D'Lila Star Combs and Jessie James Combs

(Photo by Mat Szwajkos/CP/Getty Images for CP)

Actor Giovanni Ribisi (R) and twin sister designer Marissa Ribisi

(Photo by Charley Gallay/Getty Images)

NBA ballers Robin Lopez and Brook Lopez

(Photo by Jennifer Pottheiser/NBAE via Getty Images)

Barbara Bush and Jenna Bush Hager

(Photo by Andrew H. Walker/Getty Images for UNICEF)

Actresses Mary Kate Olsen and Ashley Olsen

(Photo by Stephen Lovekin/Getty Images)

Brothers Joel and Benji Madden of Good Charlotte

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Actresses Jill and Jacqueline Hennessy

Pictured here with director Ed Gass-Donnelly (Photo by Joe Scarnici/Getty Images)