A CAS statement revealed that the IAAF had submitted revised regulations on September 29 last year and supporting evidence that would apply only to female track events between 400 metres and one mile.

A CAS panel has apparently determined that the IAAF’s supporting evidence is designed to support the original hyperandrogenism regulations as well as the revised regulations.

"However," the statement from the Lausanne-based organisation reads, "the Panel has made no ruling at this stage on the sufficiency of that evidence."

So the IAAF now has until June 19 this year to decide whether or not to maintain its support of the original hyperandrogenism regulations - for which further evidence still appears to be required - or to advise CAS on how it intends to implement the revised regulations in line with its September 29 submission.

In practical terms, this means that runners such as South Africa’s world and Olympic 800m champion Caster Semenya - whose 2009 world title win and subsequent sex verification test effectively led to the IAAF formulating its androgenism regulations - will continue to be free to compete without being limited or medically restricted.

CAS suspended the IAAF’s hyperandrogenism regulations on July 24 in 2015, “for no longer than two years”, adding that they would be declared void unless the IAAF could provide evidence proving the degree of performance advantage enjoyed by hyperandrogenic females due to their higher testosterone levels.

That deadline was extended by six months on July 28 last year.

The 2011 hyperandrogenism regulations were successfully challenged by India’s 100m runner Dutee Chand, who missed the 2014 Commonwealth Games in Glasgow after being banned following an Athletics Federation of India test that found her androgen - testosterone - levels in serum were above the 10nmol/L permitted by the IAAF.

Only the IAAF and Chand’s legal team have seen the new evidence presented to the CAS on September 29 last year.

Chand’s team challenged the IAAF’s latest proposals in October, saying the IAAF had not complied with CAS’s original request, and pointing out that the revised regulations would no longer apply to her, given that she was a sprinter.

The IAAF has been able to show that elevated natural testosterone levels provide a small performance advantage in certain female events, but not to the degree required by CAS to equate the advantage that a male athlete has over a female.