Athletes with Differences of Sex Development (DSDs, or intersex athletes) are now required to take medication to lower their naturally high levels of testosterone, according to a rule passed on May 8th, 2019, by the International Association of Athletic Federations (IAAF). To compete in events from the 400-meters to the mile, for instance, runners must have testosterone at no more than 5 nmol/L (nanomoles per liter of blood). The regulation was enforced in response to the case of South African runner Caster Semenya, who rec…
