Sidley Austin is acting for Olympic gold medallist Caster Semenya as she appeals a decision to require her to limit her testosterone levels.

The South African middle-distance runner has appealed to the Federal Supreme Court of Switzerland, challenging the recent ruling against her by the Court of Arbitration for Sport (CAS).

On May 1, CAS ruled in favour of world athletics governing body the International Association of Athletics Federations (IAAF), which had enforced a testosterone limit for individuals with disorders of sex development (DSD).

Semenya is appealing the decision on human rights grounds.

Filing her appeal, Semenya said: "I am a woman and I am a world-class athlete. The IAAF will not drug me or stop me from being who I am."

Representing Caster Semenya in the Swiss Federal Supreme Court are Sidley arbitration  partners Dorothee Schramm and David Roney, both based in the firm's Geneva office.

According to Sidley's statement, Semenya's lawyers will ask the Court to consider whether the IAAF's requirements for compulsory drug interventions "violate essential and widely recognised public policy values, including the prohibition against discrimination, the right to physical integrity, the right to economic freedom, and respect for human dignity".

Meanwhile, Bird & Bird has advised the IAAF throughout the CAS process, led by the firm's sports group co-head Jonathan Taylor QC. The firm is assisting lead counsel Ross Wenzel of Swiss firm Kellerhals Carrard throughout the appeals process. 

During the CAS proceedings, Semenya turned to dispute resolution partner Jim Bunting of Canada-headquartered firm Davies Ward Phillips & Vineberg, and Norton Rose Fulbright's Africa team head, Greg Nott.

Nott said in a statement: "It is gravely concerning that the IAAF has called on doctors to 'clarify' the gender identities of female athletes and justified medical interventions on female athletes as 'gender-affirming'.

"Such views are based not in modern science or medicine. Instead, they reflect an outdated and deeply flawed sociocultural stereotype of what it means to be a woman."

While the appeal is pending, the Federal Supreme Court of Switzerland has ordered the IAAF to suspend the implementation of the eligibility regulations against Caster Semenya, according to Sidley's statement, allowing her to compete without restriction in the female category.