Caster Semenya will not need to take testosterone-reducing medication to compete after a Swiss court temporarily suspended a new IAAF ruling.
The Olympic 800m champion, 28, last month lost her challenge to the Court of Arbitration for Sport (Cas) against the implementation of a restriction on testosterone levels in female runners.
The ruling would have affected women competing from 400m to the mile.
“I hope following my appeal I will once again be able to run free,” she said.
“I am thankful to the Swiss judges for this decision.”
The IAAF said its eligibility rule for DSD athletes will remain in place until they receive official notification from the Swiss court.
In a statement, the governing body said: “We have received no information from the Swiss Federal Supreme Court (SFT) so we cannot comment on these proceedings at this stage and our regulations will stay in place unless, and until, we hear directly from the SFT with an order to the contrary.
“We will continue to fight for what we believe is in the best interests of all female athletes in our sport.”
Semenya took her appeal to the SFT following the decision by Cas, citing the need to defend “fundamental human rights”.
Her legal representative Dr Dorothee Schramm said: “The court has granted welcome temporary protection to Caster Semenya.
“This is an important case that will have fundamental implications for the human rights of female athletes.”
In a statement to BBC Sport, the SFT said it had “super-provisionally instructed the IAAF to suspend the application of the ‘Eligibility Regulations for the Female Classification for athletes with differences of sex development’ with respect to the claimant, until the decision on the request for issuance of provisional measures”.
It added: “At present, it is not known when the Swiss Federal Supreme Courts will issue an interlocutory order concerning these provisional measures.”
In its initial judgement Cas found that the new rules proposed by the IAAF – athletics’ world governing body – for athletes with differences of sexual development (DSD) were discriminatory, but concluded that the discrimination was “necessary, reasonable and proportionate” to protect “the integrity of female athletics”.
The South African is set to compete in a 2,000m race in Paris on Tuesday, 11 June, but could instead decide to compete in upcoming Diamond League events in Oslo on 13 June and Rabat on 16 June.
- 31 July 2009: 18-year-old Semenya runs fastest 800m time of the year to win gold at the Africa Junior Championships.
- August 2009: Semenya undertakes a gender test before the World Championships in Berlin. She is unaware of the purpose of the test, with Athletics South Africa president Leonard Chuene telling her it is a random doping test.
- 19 August 2009: Semenya wins 800m world gold, breaking the world-leading mark she set in July. After her victory, the news of Semenya’s gender test is leaked to the press.
- November 2009: There are reports that Semenya’s test has revealed male and female characteristics. The results are not made public.
- 6 July 2010: Semenya is cleared by the IAAF to compete again.
- 22 August 2010: Semenya wins the 800m at an IAAF event in Berlin.
- 11 August 2012: Semenya wins 800m silver at the 2012 London Olympics. This is later upgraded to gold after Russian winner Mariya Savinov is given a lifetime ban for doping violations. Semenya is also upgraded to 2011 world gold.
- July 2014: India sprinter Dutee Chand, 18, is banned from competing after a hormone test shows natural natural levels of testosterone normally only found in men.
- 23 March 2015: Chand begins a legal challenge against the IAAF’s so-called gender tests.
- 27 July 2015: Chand is cleared to compete; the Court of Arbitration for Sport suspends, for two years, the introduction of an earlier version of IAAF rules requiring female athletes to take testosterone-suppressing medication.
- 20 August 2016: Semenya wins 800m gold at the Rio Olympics, but the decision to allow her to compete is questioned by other athletes.
- 4 July 2017: Research commissioned by the IAAF finds female athletes with high testosterone levels have a “competitive advantage”.
- 26 April 2018: The IAAF introduces new rules for female runners with naturally high testosterone.
- 19 June 2018: Semenya says she will challenge the “unfair” IAAF rules.
- 18 February 2019: Semenya’s legal hearing begins at Cas.
- 1 May 2019: Semenya loses her challenges.
- 29 May 2019: Semenya to make new appeal to Swiss federal supreme court.
- 3 June 2019: Swiss court temporarily suspends new IAAF rules, says her legal team.