South Africa's double Olympic 800m champion Caster Semenya cannot compete until she accepts to be treated with hormone-suppressing drugs, the Swiss supreme court confirmed on Tuesday. The court dismissed the appeals submitted by Semenya and her athletics federation against the decision by the Court of Arbitration for Sport on eligibility regulations for differences of sexual development (DSD) athletes. "The Court of Arbitration for Sport had the right to uphold the conditions of participation issued for female athletes with the genetic variant '46 XY DSD' in order to guarantee fair competition for certain running disciplines in female athletics," the Swiss court said.

World Athletics banned Semenya and other DSD athletes from races between 400m and a mile unless they take testosterone-reducing drugs. Semenya is classified as a woman, was raised as a woman and races as a woman. But for World Athletics, women like Semenya, with certain masculine attributes due to DSD, are classified, biologically, as men. It is a position hotly contested by South African officials. In the build-up to the 2009 world championships in Berlin, where an 18-year-old Semenya went on to win gold in the 800m, the South African had to undergo gender verification testing to confirm her eligibility to compete in the women's category. She was subsequently put on medication to reduce her testosterone levels, spending six months sidelined by World Athletics.