Caster Semenya

Mokgadi Caster Semenya OIB (born 7 January 1991) is a South African middle-distance runner and winner of two Olympic gold medals and three World Championships in the women's 800 metres. She first won gold at the World Championships in 2009 and went on to win at the 2016 Olympics and the 2017 World Championships, where she also won a bronze medal in the 1500 metres. After the doping disqualification of Mariya Savinova, she was also awarded gold medals for the 2011 World Championships and the 2012 Olympics.

Following Semenya's victory at the 2009 World Championships, she was made to undergo sex testing, and cleared to return to competition the following year. The decision to perform sex testing sparked controversy in the sporting world and in Semenya's home country of South Africa. Later reports disclosed that Semenya has the intersex condition 5α-Reductase 2 deficiency and natural testosterone levels in the typical male range.

In 2019, new World Athletics rules came into force preventing athletes like Semenya with certain disorders of sex development (DSDs) from participating in 400m, 800m, and 1500m events in the female classification, unless they take medication to suppress their testosterone levels. Semenya has filed a series of legal cases to restore her ability to compete in these events without testosterone suppression, arguing that the World Athletics rules are discriminatory.