Europe’s top human rights court ruled in favour of Olympic runner Caster Semenya on Tuesday, saying courts in Switzerland should give her a new chance to fight a requirement that female athletes with high natural testosterone take drugs to lower it.

The South African double Olympic 800m champion, 32, had approached the European Court of Human Rights in February, 2021 after losing appeals to CAS, sport’s highest court, and the Swiss Federal Tribunal (SFT) in a long-running legal battle.

The ECHR ruled, by a slender majority of four votes to three, that Semenya’s original appeal against World Athletics regulations had not been properly heard.

“The Court found in particular that the applicant had not been afforded sufficient institutional and procedural safeguards in Switzerland to allow her to have her complaints examined effectively,” ECHR said in a statement.

“The high stakes of the case for the applicant and the narrow margin of appreciation afforded to the respondent State should have led to a thorough Institutional and procedural review, but the applicant had not been able to obtain such a review.”

Semenya may now be free to challenge, once again, rules that have left her career on hold. She has a medical condition known as hyperandrogenism, which is characterised by higher than usual levels of testosterone, a hormone that increases muscle mass, strength and haemoglobin, which affects endurance.

Under the rules, in order to compete in women’s events, athletes with differences in sexual development (DSDs) that result in high testosterone levels must lower them to those of “a healthy woman with ovaries”. They may take the contraceptive pill, have a monthly injection or undergo surgery to remove testes.

World Athletics said it stood by its rules, which would remain in place for now.

“We remain of the view that the DSD regulations are a necessary, reasonable and proportionate means of protecting fair competition in the female category as the Court of Arbitration for Sport and Swiss Federal Tribunal both found, after a detailed and expert assessment of the evidence.”

The Court of Arbitration for Sport ruled in 2019 that the global governing body’s rules were necessary for fair female competition.

At the time, Semenya said the rules were discriminatory, and contraceptive pills made her feel “constantly sick”. She lost her appeal to the SFT the following year to set aside the 2019 CAS ruling.

World Athletics have consistently said the regulations are aimed at creating a level playing field for all athletes.

Semenya won gold in the women’s 800 metres at the 2016 Games and is also a three-time world champion in the distance.

The regulations, initially applied to races of 400 metres to a mile, were expanded in March to include all female track events, preventing Semenya from relaunching her career by running longer distances.