Athletics chiefs had set a Wednesday deadline for DSD athletes to submit blood samples to their medical team with a testosterone level below five nanomoles per litre, which they must maintain over the next four and a half months.
But double 800m Olympic champion Semenya posted a picture of a clenched fist with the word “resist” on Twitter on Wednesday, a signal that she will not comply.
The International Association of Athletics Federations (IAAF) has been heavily criticised for the rules, with allegations that the science is flawed, regulations ethically dubious and potential side effects unknown.
One of the most vocal have been the World Medical Association (WMA), that urged their member physicians in 114 countries not to assist in the implementation of the regulations.
But the global body has responded in a letter to the WMA, saying the rules have been developed after “many scientific publications and observations from the field during the last 15 years”.
The IAAF clarified that the regulations only apply to DSD athletes who are legally female (or intersex), have male chromosomes (XY) not female chromosomes (XX), testes not ovaries, testosterone in the male range and the ability to make use of that testosterone circulating within their bodies.
“In 46XY DSD individuals, reducing serum testosterone to female levels by using a contraceptive pill (or other means) is the recognised standard of care for 46XY DSD athletes with a female gender identity.
"These medications are gender-affirming,” the IAAF said.
The governing body added that DSD athletes would be able to compete in male events without restrictions if they chose not to take the medication.
“In any case, it is the athlete's right to decide (in consultation with their medical team) whether or not to proceed with any assessment and/or treatment.
“If she decides not to do so, she will not be entitled to compete in the female classification of any restricted event at an international competition.
“However, she would still be entitled to compete in the male classification at any competition at any level, in any discipline, without restriction; in any ‘intersex’ (or similar) classification that the event organiser may offer at any competition at any level, in any discipline, without restriction.”
The IAAF added that athletes who submit to the regulations will be assured of privacy.
“We have seen in a decade and more of research that approximately 7.1 in every 1000 elite female athletes in our sport are DSD athletes with very high testosterone levels in the male range,” the IAAF said on their website.
“The majority of those athletes compete in the restricted events covered by the regulations.”
Semenya, who last month lost an appeal to the Court of Arbitration for Sport (CAS) to halt the implementation of the regulations, which cover races from 400m to a mile, appears firm in her decision not to comply.
Along with Athletics SA, she has 30 days from the CAS verdict on May 1 to launch an appeal to the Swiss Federal Tribunal.
Repeated enquiries over whether she would do so have not been answered.