Athletics’ highly contentious testosterone limit for female competitors has been suspended for another six months, the Court of Arbitration for Sport has ruled.

The International Association of Athletics Federations (IAAF) introduced its hyperandrogenism regulations in 2009 in the wake of the controversy surrounding Caster Semenya’s gender test at that year’s World Championships.

The South African, who has since won back-to-back Olympic golds for 800 metres, was subjected to the test when she was only 18, despite her high testosterone levels being entirely natural.

But with many competitors and experts claiming she, and others with the same genetic condition, had an unfair advantage, the IAAF decided to set a testosterone ceiling for female athletes.

This meant Semenya and several others were forced to undergo treatment to reduce their levels of the hormone until Indian sprinter Dutee Chand’s similar case in 2014 galvanised critics of the IAAF rule to challenge it.

CAS, sport’s highest court, made an “interim award” in July 2015 to suspend the rule for two years, inviting the IAAF to find scientific backing for the testosterone limit.

That research, led by two French scientists, was published in the British Journal of Sports Medicine in July 2017 and formed the basis of the IAAF appeal, which had already been given an extension.

Speaking to reporters at last summer’s World Championships in London, IAAF president Lord Coe said: “I don’t want athletes being demonised but it is the responsibility of the federation to create a level playing field in female sport.

“We don’t want to turn this into a witch hunt. Nobody is choosing to cheat here. This is not an anti-doping issue – it is a biological one.

“(But) I have to protect the sport, and of course we have done this carefully.”

With the new research suggesting that female athletes with high testosterone did have a “significant competitive advantage” – particularly in 400 metres, 400 metres hurdles, 800 metres, hammer throw and pole vault – the IAAF proposed a revised rule that would only apply to track events between 400 metres and one mile.

Chand’s team challenged that proposal in October, saying the IAAF had not complied with CAS’s original request, and pointed out that it did not apply to her, a sprinter, anyway. A month later, CAS told her it thought the IAAF had complied with its request but “has made no ruling at this stage on the sufficiency of that evidence”.

Now, the Lausanne-based court has formally suspended the hyperandrogenism rule for another six months.

But, in a twist that could have fresh implications for Semenya, CAS has told the IAAF it can either stick to its 2015 rule and continue the legal battle this summer, or it can drop the rule completely or bring in the revised rule suggested last year and Chand’s case will be closed.

“If the IAAF withdraws the hyperandrogenism regulations and/or replaces them with the proposed draft regulations it has submitted, then these proceedings will be terminated,” CAS said in a statement.

This would appear to mean that this row is not over yet.