After a transgender woman lowers her level of testosterone, there is no inherent reason why her physiological characteristics related to athletic performance should be treated differently from the physiological characteristics of a non-transgender woman.
Under the recently passed (& now being considered by the Supreme Court) Idaho law, an individual whose sex is disputed for purposes of competing in athletic activities for women and girls is instructed to “verify the student’s biological sex” by providing a signed physician statement after an examination relying only on one or more of the following: the student’s reproductive anatomy, genetic makeup, or normal endogenously produced levels of testosterone.
None of these physiological characteristics alone or in any combination can “verify” sex, nor are any of them alone or in any combination accurate proxies for athletic advantage.
As noted above, one does not verify sex by a examining these characteristics, alone or in combination. A person’s sex is made up of multiple biological characteristics and they may not all align as typically male or female in a given person.
A person’s genetic make-up and internal and external reproductive anatomy are not useful indicators of athletic performance and have not been used in elite competition for decades.
A blood test is generally used to test circulating testosterone. The blood test does not distinguish between exogenous and endogenous testosterone. Exogenously administered testosterone can be identified with a urine test. However, the urine test will only determine that there is current use of exogenous testosterone. The urine test is not relevant when the person is not taking exogenous testosterone.
The urine test will not measure what endogenous testosterone levels would be absent suppression. For a person suppressing testosterone as part of a medically prescribed treatment plan for gender dysphoria, neither blood testing nor urine testing would specify testosterone levels without suppression. There is no way to test for “normally produced” endogenous testosterone without taking people off of prescribed medication, which would be dangerous.
Idaho’s new rule creates an outright bar based on endogenous testosterone without even specifying the endogenous serum testosterone level that one would need to demonstrate to “verify” sex.
Under the Idaho rule, no amount of reduction of one’s testosterone level could ever be adequate. Further more, people without active testosterone receptors experience none of the athletic impact of the hormone despite having high levels of circulating testosterone. They too would appear to be disqualified under Idaho’s rule.
The legislative findings for H.B. 500 contend that even after receiving gender-affirming hormone therapy, women and girls who are transgender have “an absolute advantage” over non-transgender girls. This assertion is based on speculation and inferences that have not been borne out by any evidence.
First, these arguments overlook the population of transgender girls and women who, as a result of puberty blockers at the start of puberty and gender affirming hormone therapy afterward, never go through a typical male puberty at all. These girls never experience the effects of high levels of testosterone and accompanying physiological changes. They go through puberty with the same levels of hormones as other girls and develop typically female physiological characteristics, including muscle and bone structure. Idaho’s law would bar them from participation in female athletics with absolutely no medical or scientific basis even based on the standards set forth in the legislative findings.
A transgender woman who has not gone through a typical male puberty is similarly situated to a woman with XY chromosomes who has complete androgen insensitivity syndrome, and it has long-been recognized that women with CAIS have no athletic advantage simply by virtue of having XY chromosomes.
The legislative findings also state that “benefits that natural testosterone provides to male athletes is not diminished through the use of puberty blockers and cross-sex hormones.
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