The future of double Olympic champion Caster Semenya is in doubt after she said she would not take medication to lower testosterone levels to comply with new rules for the 800 metres.
The 28-year-old South African won her last 800 metres race today before the introduction of the rules by the International Association of Athletics Federations (IAAF), the sport's governing body, come into effect on May 8.
Under the new rules, female athletes with high natural levels of testosterone wishing to compete in events from 400 metres to a mile must medically limit that level to under 5 nmol/L, double the normal female range of below 2 nmol/L.
Semenya also refused to clarify suggestions that she would switch to a new distance that is exempt from the IAAF rules.
Asked if she would take testosterone limiting medication, Semenya said: "Hell no."
"I'm never going anywhere," she added when asked if she might quit the sport. "At the end of the day, it's all about believing.
"It's up to God. God has decided my career and he will end my career so no human can stop me from running. I understand there's been a lot of controversy but that does not control anything."
She said: "We're doing it for the next generation. We want to inspire them.
"I believe in my legal team, they will do their best to get me back on the track."
The South African was running at the Diamond League meeting in Doha two days after the Court of Arbitration for Sport (CAS) rejected her appeal to get the IAAF's new regulations thrown out. Semenya's legal team said it was considering appealing that ruling.
Semenya cruised home on Friday as she won her 30th successive race over the distance in one minute 54.98 seconds, nearly three seconds ahead of Burundi's Francine Niyonsaba.
Semenya, given a warm reception by a sparse crowd at Doha's Khalifa International Stadium as the runners were presented at the start, bided her time before taking the lead with around 300 metres left and then powered away from the rest of the field.
Niyonsaba, Olympic silver medallist in 2016, recently revealed she had similar difference in sexual development (DSD) characteristics to Semenya.
If Semenya wants to continue with the 800 metres, she must now begin taking medication to lower her testosterone levels based on the new rules which CAS said on Wednesday were necessary to ensure fair competition.
Testosterone is a hormone that increases muscle mass, strength and haemoglobin - which affects endurance.
Semenya could compete in longer distances not affected by the rule change.
She claimed the 5,000-metres title at the South African Athletics Championships last week, an event not covered by the IAAF regulations, but in a modest time of 16:05.97, well below the qualifying standard for the world championships of 15:22.00.