When does an advantage become unfair? Empirical and normative concerns in Semenya's case.

There is a fundamental tension in many sports: human sex is not binary, but there are only two categories in which people can compete: male and female. Over the past 10 years, the International Association of Athletics Federations (IAAF) regulations have been at the centre of two notable legal disputes. The Court of Arbitration for Sport (CAS) reached two contradictory rulings: in the first case (Dutee Chand vs Athletics Federation India and IAAF), the IAAF regulations for the eligibility of athletes to compete in the female category were suspended (24 July 2015) on grounds of "discrimination against the female category"; in the latter (Caster Semenya and Athletics South Africa vs IAAF), the regulations were reaffirmed (1 May 2019) on grounds that although discriminatory, they are necessary to maintain a "level playing field" and to "protect" the female category. Although Semenya's case has paved the way for questioning existing gender norms in sport, a new stable norm has yet to emerge from her case. The pharmacological solution put forward by IAAF to the tension between fairness and inclusivity of bodies non-conforming to two sexes is not, however, the only possible solution/resolution to the case, as I aim to show in this paper. Here I present some reflections on this topic and suggest how CAS should approach the case if it hopes to resolve it.