Margaret Wambui of Kenya, who won bronze in the 800 meters behind Caster Semenya at the 2016 Olympics, said she is affected by the new rules but won't take "any type of medication" to lower her natural testosterone.
Without medication or surgery, some female runners won't be allowed to compete at anymore international meetings this season, including this year's world championships.
"It's wrong of (the) IAAF to ask us to take medicine to alter our natural body function," Wambui said Tuesday, speaking Swahili in an interview in Kenya.
She said she was unsure what side effects any medication or treatment might have on her.
The 23-year-old Wambui, the world junior champion in the 800 in 2014, compared the regulations to "losing your job."
"This ruling is very unfair," she said. "I have grown up knowing that I want to do athletics as a career and achieve a lot through it. Why wait for me to establish myself as an 800-meter athlete then tell me that I need to take medication to compete in the same event?
"The ruling has affected me greatly because you are not sure of what to train for ... this season I was focusing on the world championships and Diamond League races but all that effort has gone to waste."
Semenya, a two-time Olympic 800-meter champion, lost her case against the IAAF at the Court of Arbitration for Sport, allowing track's governing body to implement testosterone limits in races from 400 meters to one mile.
Female athletes who have one of a specific set of conditions that cause testosterone levels higher than the typical female range now have to lower those levels to be eligible to compete at international events.
The IAAF provides three options to lower the hormone levels: Daily contraceptive pills, a monthly hormone-blocking injection or surgery.
That has been criticized as unethical by the World Medical Association, which has advised doctors not to prescribe the medication or treatment if it's not requested and there is no medical need and it's solely for athletic purposes. The contraceptive pills and hormone-blocking injections would have negative side effects.
Wambui said she received a letter from the IAAF about a week ago informing her that her testosterone levels were higher than the allowed level. Athletes wanting to compete at the world championships in Doha, Qatar, in September and October had to start lowering their testosterone by May 8 to be eligible.
"My family is very disappointed by this decision by (the) IAAF," she said. "After I received the letter I went back home and spent a week with my mother trying to make her understand what's happening."
Wambui's decision to publicly declare she is affected by the rules means all three medalists in the 800-meter race at the 2016 Rio de Janeiro Olympics have said they have a condition that causes high levels of natural testosterone.
Semenya and silver medalist Francine Niyonsaba of Burundi have also said they are affected. Niyonsaba was highly critical of the rules, while Semenya was adamant that she won't take medication when she ran at a Diamond League meet at the beginning of the month.
Wambui said she is considering switching to the 100 and 200 meters, events not affected by the rules. Semenya has entered a 3,000-meter race in the United States in June.
But there's also still a chance of an appeal against the IAAF rules.
Semenya's lawyers say they are considering that, while the South African government has announced there will be an appeal on behalf of the country's national track federation.
An appeal against the CAS decision must be lodged by May 31.
Imray reported from Somerset West, South Africa.
More AP sports: https://apnews.com/apf-sports and https://twitter.com/AP_Sports
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.