How did Santhi Soundarajan fail her gender test?

In this day in age, most of us understand that gender identity can be pretty complicated from a social, cultural and psychological perspective. But the idea that gender can be complicated from a physical perspective -- that a female athlete can be deemed non-female for the purposes of competition -- seems a bit bizarre. As it turns out, gender is as much a physical puzzle as it is a social one. There is no one test that can determine with scientific certainty whether someone is male or female. There is only a battery of tests that can evaluate the various aspects of physical gender distinction, and there are various opinions about which of those tests should count the most.

In a recent case of an athlete failing a gender test, in December 2006, 25-year-old Santhi Soundarajan was stripped of her silver medal for the 800-meter race in the Asian Games. The first gender tests in the 1960s, which were mandatory for all female athletes competing at the international level to make sure they weren't actually men, involved the athletes undressing in front of a group of doctors. This practice ended pretty quickly due to outrage among the female athletes. The current gender test, which only takes place when a claim is filed against a specific athlete, is far more scientific, though chances are Ms. Soundarajan would say it's just as humiliating for the athlete.

While reports of what exactly took place in Soundarajan's gender test have not been released, today's gender tests typically follow a general path that includes an anatomical evaluation, a genetic analysis, a chromosomal analysis and a psychological evaluation.

The physical exam that checks for male/female anatomical distinctions is fairly straightforward. A gynecologist looks for the primary and secondary sex characteristics associated with womanhood, including female sex organs, menstruation, and a lack of facial and chest hair. While the exam is straightforward, the results are not: Females can be born with anatomical abnormalities; female athletes may not menstruate because they have too little body fat; and the presence or absence of body hair is never an absolute distinction between males and females, only a general guideline. So the blood test comes next.

The blood test is first looking to confirm certain physiology differences between the sexes. For example, lab tests will check for appropriate levels of sex hormones. Men typically have more testosterone in their bodies, while women typically have more estrogen. Of course, both sexes have both hormones in their bodies, and there are no absolute rules for how much testosterone and estrogen determines a woman. Genetics, on the other hand, may be a little easier to pin down -- at least on the surface.

Most of us know that every cell in the body contains genetic information, and that some of that genetic information relates to gender. A woman usually has two X chromosomes in each of her cells, while a man usually has an X chromosome and a Y chromosome. To check for these gender-determining chromosomes, doctors create a karyotype, which is essentially a layout of all the chromosomes in a single cell. If there's a Y there, the assumption is that the cell belongs to a male. The problem is that this assumption isn't always true. Sometimes, a woman will have an occasional Y chromosome -- a genetic abnormality; and other times, she'll have the XY pair in all of her cells as if she were a male, even though she has a vagina, breasts, high estrogen levels and other markers of femaleness. This can happen when the activator on the Y chromosome -- the SRY gene -- doesn't work. This is where the gender test looks next.

Examining the Y chromosome that's present in a female cell, a doctor will check to see if the SRY gene is absent, mutated, damaged or disabled. If this gene doesn't work, the process of fetal differentiation is affected. Until a fetus is seven weeks old, it is neither male nor female. At the time of differentiation, either the Y chromosome begins the process of creating maleness or it doesn't. Typically, it is the absence of the Y chromosome that triggers the development of femaleness. However, a faulty SRY gene on the Y chromosome can have the same effect.

But the SRY trigger isn't the only factor in developing maleness, and even cells with a working SRY gene can end up living in the body of a functioning female. A dysfunction in any of the many later stages of male-female development, triggered by a number of other genes that play a specific role in gender distinction from the womb through adolescence, can affect the genetic, chromosomal and physical traits that any man or woman possesses. In the end, determining gender is a very complex process and is often one without a definite answer. If someone has lived her entire life as a woman, has breasts and a vagina and a uterus and a Y chromosome -- is it only that last factor that determines her gender? Does the presence of a Y chromosome make a man? Does the presence of a Y chromosome but a damaged SRY gene make a woman just as clearly as an XX chromosome pair would?

It's unclear what role the psychological evaluation plays in determining femaleness, although its inclusion implies that personal gender identity -- the way one sees oneself in terms of sexuality -- is taken into consideration in a gender test.

According to an article in the San Francisco Chronicle, an anonymous official in the know has reported that Ms. Soundarajan's tests revealed more Y chromosomes than are usually present in the genetic make-up of a female. The same official has said there are no indications the athlete ever had a sex-change. At the Asian track-and-field championships in 2005, Ms. Soundarajan was also asked to take a gender test, and she passed it.

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