CASTER SEMENYA has asked the Court of Arbitration for Sport to rule the International Association of Athletics Federations’ testosterone regulations “unlawful.”

CAS yesterday issued a statement saying it had been asked to rule on the IAAF regulation compelling some female athletes to medically lower naturally occurring testosterone, which comes into effect on November 1.

The South African, a two-time Olympic and three-time world 800 metres champion, has hyperandrogenism, a medical condition characterised by excessive levels of male sex hormones such as testosterone.

Athletics’ world governing body is seeking to introduce the IAAF Eligibility Regulations for Female Classification, but it will not go unchallenged.

The regulations, which were announced in April, are designed by the IAAF to tackle indications that women with higher levels of natural testosterone enjoy an unfair advantage in competition. Female athletes competing in events from 400m to the mile will be subject to the new rules.

Gregory Nott, director of law firm Norton Rose Fulbright and representing Semenya, said in a statement on Monday: “This is a landmark case concerning international human rights and discrimination against women athletes with major consequences for gender rights which are jealously protected by the South African Bill of Rights.

“We are honoured to represent Ms Semenya and advance a position that protects all affected women.”