In a recently published French-language procedural order, the Swiss Supreme Court dismissed a request by Olympian middle-distance runner, Caster Semenya (Semenya), to stay the effects of a Court of Arbitration for Sport (CAS) award. It also reversed its prior ruling suspending the application of the International Association of Athletics Federation's (IAAF) Eligibility Regulations for the Female Classification - Athletes with Differences of Sex Development (DSD Regulations) until the issuance of a decision on the merits of the challenge to the CAS award.

Under the DSD Regulations, Semenya is obliged to take medication reducing her innate testosterone level if she wants to participate in certain women's athletic competitions. Semenya, who wishes to compete naturally, requested arbitration at the CAS arguing that the DSD Regulations unfairly discriminated against her on the basis of sex and/or gender. A CAS panel ruled that whilst the DSD Regulations are discriminatory in nature, they were necessary and proportionate with respect to athletes with differences in sexual development to ensure fair competition in women's athletics.

Semenya initiated setting aside proceedings before the Supreme Court on the grounds that the CAS award was contrary to public policy. She supplemented her challenge with a request for the stay of the effects of the CAS award and a request for provisional measures suspending the implementation of the DSD Regulations against her.

On an ex parte basis, the Supreme Court initially lifted the applicability of the DSD Regulations with regard to Semenya. However, in an unprecedented move and after hearing the IAAF's arguments, the Supreme Court made an inter partes procedural order available to the public. By way of this order, the Supreme Court reversed the ex parte order and denied Semenya's request that the DSD Regulations be suspended pending the resolution of her challenge. In its ruling, the Supreme Court set out the criteria it applies when deciding whether to grant provisional measures and a stay of enforcement of an award. In that framework, it found that Semenya's challenge to the CAS award, based on an alleged violation of public policy, failed to establish that her appeal was, on a prima facie basis, very likely to be well-founded. It also refused to temporarily stay the effects of the CAS award. The Supreme Court's decision on the merits of Semenya's appeal remains forthcoming. (Decision 4A_248/2019 (29 July 2019).)