Human Heredity 11th Edition by Michael Cummings

Exercise 20

Sex Testing in the Olympics-Biology and a Bad Idea
Success in athletics, including the Olympics, is often a prelude to a high-visibility career, financial rewards, and acclaim. Because the stakes are so high, several methods are used to guard against cheating in competition. Athletes in many international events are required to submit urine samples (collected while someone watches) for drug testing. In other cases, urine testing is done at random in an attempt to detect and thus eliminate the use of steroids or performance- enhancing drugs. In the 1960s, rumors about males attempting to compete as females led the International Olympic Committee (IOC) to require sex testing of all female athletes, beginning with the 1968 Olympic Games.
The IOC's test involved analysis of Barr bodies in cells collected by scraping the inside of the mouth. In genetic females (XX), the inactivated X chromosome forms a Barr body, which can be stained and viewed in a microscope. Genetic males (XY) do not have a Barr body. The procedure is noninvasive, and females were not required to submit to a physical examination of their genitals. If sexual identity was called into question as a result of the test, a karyotype was required, and if necessary, a gynecological examination followed.
In both theory and practice, the IOC's test was a bad idea for several reasons. Barr-body testing is unreliable and leads to both false positive and false negative results. It fails to take into account phenotypic females who are XY with androgen insensitivity and other genetic conditions that result in a discrepancy between chromosomal sex and phenotypic sex. In addition, the test does not take into account the psychological, social, and cultural factors that enter into one's identity as a male or a female. Ironically, no men attempting to compete as women were identified, but the test unfairly prevented females from competition. Of the more than 6,000 women athletes tested, 1 in 500 had to withdraw from competition as a consequence of failing the sex test. The Spanish hurdler Maria Martinez Patino led a courageous fight against sex testing. She has complete androgen insensitivity, was raised as a female, and competed as a female. However, she had an XY chromosome set, not XX, and did not have any Barr bodies. After she was stripped of her athletic scholarship and her running times were erased from records in Spain, she told her story in the press and helped persuade the IOC to drop chromosome testing.
The IOC and the International Amateur Athletic Federation (IAAF) instituted a new test, based on recombinant DNA technology, to detect the presence of the maledetermining gene SRY , which is carried on the Y chromosome. This test was instituted at the 1992 Winter Olympics. A positive test makes an athlete ineligible to compete as a female. However, the test was again flawed because it fails to recognize several chromosomal combinations that result in a female phenotype even though an SRY gene is present. At the 1996 Summer Olympic Games in Atlanta, 8 of 3,387 females were SRY positive; 7 of the 8 had partial or complete androgen insensitivity. Again, no males attempting to compete as females were identified.
In 2012, the IOC began using tests that measure levels and the body's response to the male hormone testosterone. The apparent rationale is that male and female performance levels differ because of different testosterone levels. Women whose levels are within the normal range for males may not be allowed to compete. However, there is significant variation in levels of male sex hormones in women, some of which overlap with the levels found in males. This makes it impossible to establish a baseline level to determine who is a "female" by this test. The IOC no longer requires testing of all female athletes, and relies on case by case evaluation of those suspected of gender disorders. It is hoped that even this test will pass from the scene and that the IOC and other athletic federations will admit that there is no single test that can distinguish females from males.
Do you think that XY individuals with complete androgen insensitivity (CAIS) have an unfair advantage in competing with XX individuals in athletics? Why or why not?