Why We Can’t Define Sex Through Testosterone

How Caster Semenya’s case leads to broader consequences for sex identification and the participation of transgender athletes in sports

South Africa’s Caster Semenya (front) competes in the Women’s 800m Round 1 during the athletics event at the Rio 2016 Olympic Games. Photo: Antonin Thuillier/Getty Images

Sex is the first label we are given at birth, if not before, when an inspection of our genitalia determines whether we’re identified by one checkbox or another…