This paper examines the regulatory gaps in the protection of athletes’ gender rights in sport. The regulation of human rights in sport is increasingly being scrutinised and at the same time, the societal parameters of sex and gender identity are shifting. Together, these current developments present a regulatory riddle when determining how to balance the interests of sport with the protection of non-conforming athletes’ rights, who may not strictly fit into the binary categories of sport. Despite a strong human rights framework protecting gender rights, the complex relationship between law and sport leaves athletes in a vulnerable position, with limited accountability of sports bodies and restricted access to a legal remedy. Drawing upon existing recommendations, this paper offers original insight for resolving the riddle, such as the establishment of an anti-discrimination in sport unit to enforce human rights in sport.