Russian pole vaulter and International Olympic Committee (IOC) member Yelena Isinbayeva has waded into the Caster Semenya dispute by claiming female athletes with high testosterone levels have a "colossal advantage".
The International Association of Athletics Federations (IAAF) hopes to introduce rules which would see athletes with high levels forced to take medication or to compete against men.
South Africa's Semenya, a double Olympic and triple world champion over 800 metres and by far the most high-profile athlete who the rules would impact, is challenging the IAAF at the Court of Arbitration for Sport (CAS).
A verdict is due in late April with the IAAF proposing to enforce the rules between 400m and the mile.
Critics argue Semenya is simply competing naturally but IAAF President Sebastian Coe insists the rule is needed to ensure a level playing field.
Isinbayeva, who won Olympic gold at Athens 2004 and Beijing 2008, told Russia Today: "The rules should be applied to everyone, there should be no exceptions.
"There should be no exceptions or concessions, otherwise we cannot talk about fair competition.
"Girls with lower testosterone level have minimal chances to win.
"That's why rules implemented by the IAAF should be applied to everyone, including athletes with biological specifics.
"There should be no complaints, if such athletes want to compete against women they should be obliged to reduce testosterone level.
"No one infringes on their rights to take part in athletics events, but they should understand they have a colossal advantage."
The verdict in the case was delayed until next month after a decision had originally been due last week.
The CAS revealed additional submissions had been received and both sides agreed to the delay.
A week of hearings were held in Lausanne with witnesses including Semenya and Coe.
In October, the IAAF delayed the implementation of their new rules to await the proceedings with the CAS describing the case as one of the "most pivotal" they had heard.
Coe last week claimed "no woman would ever win another title or another medal or break another record in our sport" if the rules did not come in.
In response, the 28-year-old Semenya accused Britain's double Olympic champion of "reopening old wounds".
The United Nations Human Rights Council are among others to have commented, claiming the IAAF's plans are "unnecessary, humiliating and harmful".
Isinbayeva's support of the IAAF stance is in contrast to her battle with the governing body and Coe over the Russian doping crisis.
The triple world champion has been a strong critic of the country's suspension by the IAAF, which was enforced in 2015 after evidence of a widespread cheating scheme emerged.
Russian track and field athletes, including Isinbayeva, were barred from competing at the Rio 2016 Olympics and the IAAF ban on the country remains in place.
It means Russians still have to meet strict criteria in order to compete at international events and can only do so under an neutral flag.
Despite missing Rio 2016, Isinbayeva, who holds the women's pole vault world record of 5.06m, was still elected as a member of the IOC's Athletes' Commission at the Games.