"We understand what kind of struggle it is," Jack Grafe told "GMA." A set of twin brothers who transitioned from female to male are sharing their story in hopes of helping others who may be struggling ...

Research suggests that males and females differ in their experience of pain, but up until now, no one knew why. Research suggests that males and females differ in their experience of pain, but up ...

The study measured “rank” within the bonobo communities by tallying how many times females won conflicts with males. Females usually came out on top. Photograph by Christian Ziegler By banding ...