A decision to test female contenders for the Beijing 2008 Olympics to see if they are men has caused uproar.
Any participating female who is suspected of being a male will be evaluated from their external appearances by experts and undergo blood tests to examine their sex hormones, genes and chromosomes for sex determination, according to Prof. Tian Qinjie of Peking Union Medical College Hospital.
Initial test results would be available in three days, while an official result takes seven days.
The tests were first introduced in the 60s to catch out Olympic cheats who tried to pass off men as women to win events and up until 1999, every female had to be tested.
The idea was scrapped because of the controversy surrounding the procedure and the fact that only women are tested.
Chromosomal abnormalities may cause a woman to fail a test, even though it gives her no competitive advantage, says the New York Times.
Also, if a female athlete fails a test she must have a physiological examination, which many consider invasive and a privacy violation.
Xinhua news agency reports that Polish Olympic winner Ewar Kobukkowska was the first athlete to be banned after she failed the early form of a chromosome test in 1967.
She won a gold medal in the women’s 4 X 100 metre relay and the bronze in the women’s 100 metre sprint at the 1964 Summer Olympics in Tokyo.
She was found to have a rare genetic condition that gave her no advantage over other athletes, but was nonetheless banned from competing in the Olympics and professional sports.
At the 1996 Atlanta Olympics, eight athletes failed the tests but were all cleared by subsequent examinations.
In another case, Indian middle distance runner Santhi Soundarajan attempted suicide after she failed the sex determination test at the 2006 Asian Games and was stripped of her medal.
The Beijing Games begin on 8th August.