The double Olympic 800m champion Caster Semenya appears to have lost her long-running legal battle against regulations requiring women with high testosterone to take medication to compete internationally between 400m and a mile. A Swiss federal tribunal said on Tuesday that it supported a decision by the court of arbitration for sport last year that track and field’s policy for athletes with differences in sex development (DSD) was “necessary, reasonable and proportionate” to ensure fair competition in women’s sport. “Based on these findings, the Cas decision cannot be challenged,” the tribunal said. “Fairness in sport is a legitimate concern and forms a central principle of sporting competition. It is one of the pillars on which competition is based.” It now looks impossible for Semenya, the London 2012 and Rio 2016 gold medallist, to defend her title in Tokyo. She responded to the news by accusing World Athletics of being on the “wrong side of history”. “I am very disappointed by this ruling, but refuse to let World Athletics drug me or stop me from being who I am,” she said. “Excluding female athletes or endangering our health solely because of our natural abilities puts World Athletics on the wrong side of history. I will continue to fight for the human rights of female athletes, both on the track and off the track, until we can all run free the way we were born.” The South African was almost unstoppable until World Athletics implemented a new policy for DSD athletes, including Semenya, that compelled them to reduce their testosterone levels to less than 5 nmol/L if they wanted to compete in elite events between 400m and a mile. It argued the policy was justified because more than 99% of females have around 0.12-1.79 nmol/L of testosterone in their bodies – while DSDs are in the male range of 7.7-29.4 nmol/L. Last year Cas upheld that policy, saying it was fair because DSD athletes, including Semenya, had a significant advantage in size, strength and power from puberty onwards because of their elevated testosterone levels. In a statement World Athletics said it was “very pleased” that the highest court in Switzerland had joined with the highest court in sport in endorsing its arguments. “World Athletics has always maintained that its regulations are lawful and legitimate, and that they represent a fair, necessary and proportionate means of ensuring the rights of all female athletes to participate on fair and equal terms,” it said. “It has rejected the suggestion that they infringe any athlete’s human rights, including the right to dignity and the right to bodily integrity.” Semenya, who is also a three-time world champion, could still appeal to the European court of human rights. However in its statement the Swiss federal tribunal appeared to suggest that such an appeal would be unlikely to succeed. “The European Court of Human Rights also attaches particular importance to the aspect of fair competition,” the tribunal said. “In addition to this significant public interest, the Cas rightly considered the other relevant interests, namely the private interests of the female athletes running in the ‘women’ category.”