South Africa's track and field federation had been asked to conduct a gender test on an 800-meter runner amid concerns she does not meet the requirements to compete as a woman.
Caster Semenya, 18, is a favorite in Wednesday's 800 final at the world championships.
The world track and field federation requested the gender test about three weeks ago, after Semenya burst onto the scene by improving her personal bests in the 800 and 1,500 by huge margins.
IAAF spokesman Nick Davies said the "extremely complex, difficult" test has been started but that the results were not expected for weeks.
The verification requires a physical medical evaluation, and includes reports from a gynecologist, endocrinologist, psychologist, an internal medicine specialist and an expert on gender.
"So we're talking about reports that are very long, very time consuming," Davies said.
Semenya qualified for Wednesday's final with the best time of 1 minute, 58.64 seconds. She posted the world's top time this year of 1:56.72 three weeks ago at the African junior championships in Bambous, Mauritius.
It was not clear what would happen if Semenya were to medal in Wednesday's final and the test results determined she does not meet the requirements to compete.
"I can't say that if 'X' happens in the future that we will, for example, retroactively strip results. It's legally very complex," Davies said.
"If there's a problem and it turns out that there's been a fraud ... that someone has changed sex, then obviously it would be much easier to strip results," Davies added. "However, if it's a natural thing and the athlete has always thought she's a woman or been a woman, it's not exactly cheating."
He said a decision in such instances is "done on a case by case basis."
"It's something that would have to be considered by the legal experts at that time," Davies said.
TheDancinMonarch wrote:
First saw her/him on TV earlier this week and the first thing I said was, "Are they sure this is a woman?"
Definitely. Just by looking at the picture it's easy to tell she doesn't look "natural". On a blog I was reading there was talk of her/him being a possible hermaphrodite. In any event, the results should prove interesting.
In any event, the results should prove interesting. 
