The biomedical perspective views the physiology of trans women’s bodies as the source of perceived unfairness, with medicalized interventions (such as estrogen supplementation and testosterone suppression) as the resolution. More specifically, this perspective holds that sexual dimorphism between those assigned male at birth (AMAB) and those assigned female at birth (AFAB) is the reason for athletic differences. **Testosterone measures and boundaries are typically chosen as defining characteristics of manhood and womanhood in the context of sport and are used as the predominant marker to predict and level sex-related athletic advantage and the means for inclusion criteria. The research findings in the biomedical area are inconclusive.**Studies which make conclusions on pre- and post-hormone replacement therapy (HRT) advantage held by trans women athletes have used either cis men or sedentary trans women as proxies for elite trans women athletes. These group references are not only inappropriate for the context but produce conclusions that cannot be applied to elite trans women athletes. Further, there is little scientific understanding about the attributes or properties of HRT, namely testosterone suppression and estrogen supplementation, on the physiology and athletic ability of trans women athletes. This ignores the potential for estrogen supplementation to reduce Lean Body Mass (LBM), and for testosterone suppression to produce holistic health disadvantages.
Currently, there is no direct or consistent research suggesting transgender female individuals (or male individuals) have an athletic advantage at any stage of their transition (e.g. cross-sex hormones, gender-confirming surgery) and, therefore, competitive sport policies that place restrictions on transgender people need to be considered and potentially revised.
The notion of transgender girls having an unfair advantage comes from the idea that testosterone causes physical changes such as an increase in muscle mass. But transgender girls are not the only girls with high testosterone levels. An estimated 10 percent of women have polycystic ovarian syndrome, which results in elevated testosterone levels. They are not banned from female sports. Transgender girls on puberty blockers, on the other hand, have negligible testosterone levels. Yet these state bills would force them to play with the boys. Plus, the athletic advantage conferred by testosterone is equivocal. As Katrina Karkazis, a senior visiting fellow and expert on testosterone and bioethics at Yale University explains, “Studies of testosterone levels in athletes do not show any clear, consistent relationship between testosterone and athletic performance. Sometimes testosterone is associated with better performance, but other studies show weak links or no links. And yet others show testosterone is associated with worse performance.” The bills’ premises lack scientific validity.
Results: In this cohort of athletes, TW had similar testosterone concentration (TW 0.7±0.5 nmol/L, CW 0.9±0.4 nmol/), higher oestrogen (TW 742.4±801.9 pmol/L, CW 336.0±266.3 pmol/L, p=0.045), higher absolute handgrip strength (TW 40.7±6.8 kg, CW 34.2±3.7 kg, p=0.01), lower forced expiratory volume in 1 s:forced vital capacity ratio (TW 0.83±0.07, CW 0.88±0.04, p=0.04), lower relative jump height (TW 0.7±0.2 cm/kg; CW 1.0±0.2 cm/kg, p<0.001) and lower relative V̇O2max (TW 45.1±13.3 mL/kg/min/, CW 54.1±6.0 mL/kg/min, p<0.001) compared with CW athletes. TM had similar testosterone concentration (TM 20.5±5.8 nmol/L, CM 24.8±12.3 nmol/L), lower absolute hand grip strength (TM 38.8±7.5 kg, CM 45.7±6.9 kg, p=0.03) and lower absolute V̇O2max (TM 3635±644 mL/min, CM 4467±641 mL/min p=0.002) than CM.
Conclusion: While longitudinal transitioning studies of transgender athletes are urgently needed, these results should caution against precautionary bans and sport eligibility exclusions that are not based on sport-specific (or sport-relevant) research.
So even those highly motivated to prove trans women are disproportionately advantaged have difficulty tapping it. As for combat sports, don’t forget Joe Rogan as well female MMA athletes ended up apologizing to Fallon Fox for all the transphobic BS they had spewed at the time.