The Colorado Rush, a gay rugby team in Denver, at practice. "I've always thought of myself as ... the rugby player that happens to be gay," says Skyler Meyer. "I never want to be the gay man who happens to play rugby." Luke Runyon/KUNC hide caption

itoggle caption Luke Runyon/KUNC

Johnson with her fellow researcher and sometimes husband, William Masters. The pair helped legitimize the study of human sexuality. AP hide caption

itoggle caption AP

A male fruit fly (Drosophila melanogaster) Jan Polabinski/iStockphoto hide caption

itoggle caption Jan Polabinski/iStockphoto