Trans women in sports: recent research summary
The conscious exclusion of male athletes from female sports has enabled the production of elite level of female athletes rather than male. To suppose that male advantage in sports could be removed would require extraordinary evidence. There is currently no substantial scientific evidence that this male biological advantage can be removed.
Testosterone suppression as a way to fairly include trans women in female sports has been highly contested and largely discredited. Over the past two decades there have been over a dozen published research papers for a total of some 800 participants which investigated the effect of testosterone suppression on muscle mass, and in some instances muscle strength, in transgender women. Below is a summary of the most recent research from 2020-2022: Summary:
Wiik et al., 2020: There was minimal loss of muscle mass or strength in transgender women following 12 months of testosterone suppression, and some subjects gained strength. After treatment transgender women remained 48% stronger, with 35% larger quadriceps mass compared with the control population of females.
Roberts et al., 2020 found that transgender women still retain a competitive advantage 2 years after hormone treatment. Transwomen still had a 9% faster mean run speed after the 1 year period of testosterone suppression that is recommended by World Athletics for inclusion in women’s events.
Hilton and Lundberg, 2021 conclude: “Superior anthropometric, muscle mass and strength parameters achieved by males at puberty, and underpinning a considerable portion of the male performance advantage over females, are not removed by the current regimen of testosterone suppression permitting participation of transgender women in female sports categories. Rather, it appears that the male performance advantage remains substantial.”
Harper et al., 2021 found: “Hormone therapy decreases strength, LBM [lean body mass] and muscle area, yet values remain above that observed in cisgender women, even after 36 months. These findings suggest that strength may be well preserved in transwomen during the first 3 years of hormone therapy.” Heather et al., 2022 provides a critical review, reporting: “The existing data suggests that lowering testosterone to less than 10 nmol/L for 12 months decreases muscle mass but not to biological female levels and despite the decrease in mass, muscle strength can be maintained, especially if concurrently exercising. Estrogen therapy does not affect most of the anatomical structures in the biological male that provide a physiological benefit. Hemoglobin levels are lowered by estrogen therapy, and consequently, maximum aerobic effort may be lower, but this parameter will only be manifested if testosterone levels are suppressed to levels within the biological female range and maintained for extended periods of time. Reported studies show it is difficult to continuously suppress testosterone in transgender women. Given that the percentage difference between medal placings at the elite level is normally less than 1%, there must be confidence that an elite transwoman athlete retains no residual advantage from former testosterone exposure, where the inherent advantage depending on sport could be 10–30%. Current scientific evidence can not provide such assurances and thus, under abiding rulings, the inclusion of transwomen in the elite female division needs to be reconsidered for fairness to female-born athletes.”
