Paris – South Africa’s double Olympic 800m champion Caster Semenya on Tuesday accused world athletics’ governing body the IAAF of using her as a “human guinea pig”.

“The IAAF used me in the past as a human guinea pig to experiment with how the medication they required me to take would affect my testosterone levels,” said Semenya.

The South African is locked in a bitter dispute with the IAAF over the federation’s rule requiring women with higher than normal male hormone levels, a condition known as hyperandrogenism, to artificially lower their testosterone to compete in races at distances of 400m to the mile.

“Even though the hormonal drugs made me feel constantly sick, the IAAF now wants to enforce even stricter thresholds with unknown health consequences,” Semenya said in a statement.

“I will not allow the IAAF to use me and my body again. But I am concerned that other female athletes will feel compelled to let the IAAF drug them and test the effectiveness and negative health effects of different hormonal drugs. This cannot be allowed to happen.”

The athlete, who won the women’s 800 metres at the 2012 and 2016 Olympics, unknowingly underwent a gender test shortly before she won gold at the 2009 Berlin world championships which allegedly showed she had both male and female characteristics.

She was forced to spend eight months out, the IAAF clearing her to compete again in July 2010.

Switzerland’s top court last week rejected an IAAF request to re-impose their rules on testosterone after it had temporarily suspended them following an appeal by Semenya.

Semenya had contested a decision by the Swiss-based Court of Arbitration for Sport which previously found that the rules were “discriminatory” but “necessary” to ensure fairness in women’s athletics.

The athlete’s lawyers, however, issued a statement on Tuesday welcoming the “publication by the CAS of the arbitral award setting out the CAS Panel’s reasoning and limitations in making its award”.

The CAS Panel states that “Ms. Semenya is a woman. At birth, it was determined that she was female, so she was born a woman”.

“She has been raised as a woman. She has lived as a woman. She has run as a woman. She is – and always has been – recognised in law as a woman and has always identified as a woman.”

Semenya’s lawyers said that the “IAAF has taken it upon itself to decide who is, and who is not, woman enough in the eyes’ of the IAAF, and to discriminate on that basis”.

“While the IAAF publicly claims that it is not engaged in sex testing, the CAS Award makes it clear that the IAAF is doing exactly that,” they said.

The IAAF reacted by maintaining that in sport “biology has to trump gender identity to ensure fairness”.

“Having the arguments of all parties and the detailed findings of the CAS Panel in the public domain will help to foster greater understanding of this complex issue…

“… and to demonstrate the balance it is necessary to draw between the right for any individual to choose their legal sex and/or gender identity, which the IAAF fully supports and respects, and the need for sport to create and defend a protected category for females, with eligibility for this category based on biology and not on legal sex or gender identity.”

“Sport is one of only a few, narrow sectors of society in which biology has to trump gender identity to ensure fairness,” the IAAF said.

“To define the female category based on something other than biology would be category defeating and would deter many girls around the world from choosing competitive and elite sport after puberty.

“The IAAF considers that the DSD (difference of sex development) Regulations are a necessary, reasonable and proportionate means of protecting fair and meaningful competition in elite female athletics, and the CAS agreed.”