Indian runner Santhi Soundararajan may be stripped of her Asian Games silver medal, after the Indian Olympic Association announced Monday that she had failed a gender test shortly after competing. Is a "gender test" as simple as it sounds?
No. You can't tell for sure if an athlete is a man or a woman just by glancing at his or her genitalia. That's because some people are born with ambiguous sex organs, and others have a visible anatomy that doesn't match up with their sex chromosomes. Fears that male Olympic athletes might be competing as women led to mandatory physicals for females in the 1960s, which soon gave way to chromosome-based gender testing. Officials collected mouth scrapings and ran a simple test for the presence of two X chromosomes. The method proved to be unreliable, since it's possible for a biological male to have an extra X chromosome (XXY) or a female to only have one X chromosome.
The gender of an embryo is determined during its early development. If certain sex-determining genes are present, the fetus will develop testes, which in turn produce testosterone. It's the testosterone that makes the fetus into a boy. The genes that are important for this switch are generally located on the Y chromosome. By the 1992 Winter Games, officials started testing for one of these genes, called SRY—if you had it, you couldn't compete as a woman.
That test didn't work, either. Having the SRY gene material, or even a Y chromosome, doesn't always make you a man. Some people born with a Y chromosome develop all the physical characteristics of a woman except internal female sex organs. This can result from a defect in one of the genes that allows the body to process testosterone. Someone with this condition (known as "androgen insensitivity syndrome") might be XY, and she might develop testes. But she'll end up a woman, because her body never responds to the testosterone she's producing. Other signs of AIS include hairless genitalia and the absence of menstruation. (There are reports that Soundararajan had "not attained puberty yet.")
Since testosterone helps in building muscle and strength, a case of androgen insensitivity syndrome wouldn't give an XY-female athlete any kind of competitive advantage; if anything, it would be a liability. Seven of the eight women who tested positive for Y-chromosomal material during the 1996 Summer Games in Atlanta had some form of AIS. They were allowed to compete.
By the late 1990s, the International Olympic Committee turned to a more comprehensive evaluation by a panel of specialists to account for all these ambiguities. The panel now includes gynecologists, endocrinologists, psychologists, and experts on transgender issues. The examiners still test for the Y-chromosomal genes; gynecologists perform physical exams; endocrinologists diagnose gene disorders and resulting hormonal conditions; and athletes may be given psychological help to deal with the situation.
Mandatory gender testing of Olympic athletes was stopped altogether in 1999, but Olympic and IAAF rules allow for gender tests if an athlete's gender is challenged by another athlete or team, or event officials. (Soundararajan's screening is said to have originated with such a protest.) Some athletes are called in for a complete exam after they give their urine sample during a doping test. Officials watch the whole process to make sure the athletes don't swap in someone else's pee, so they can flag anyone whose genitalia don't appear consistent with his or her stated gender.
Athletes who have undergone sex-reassignment are allowed to compete alongside their new gender, provided they follow regulations.
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Explainer thanks Dr. Myron Genel of Yale University, Dr. Joe Leigh Simpson of Baylor University, and Dr. Louis Elsas of the University of Miami.