Transgender women and competitive sports: Considerations from Endocrinology

The participation of transgender women (TW) in high-level competitive sports increases every year, as does the interest of sports organizations in finding solutions that allow their inclusion without compromising the principle of equity governing high-level sports. However, the binary categorization of sports, influenced by the impact of sex hormone on physical performance, creates challenges for the inclusion of TW in the female category. This study aimed to understand the impact of gender-affirming hormone therapy (GAHT) on various athletic performance variables and to compare results with those obtained in cisgender populations.

Review of cross-sectional and longitudinal studies that included TW (preferably athletes) undergoing GAHT.

Significant decreases in hematocrit, total serum testosterone, lean body mass, strength, and muscle area were observed after 12 mo of GAHT, with increases in fat mass. Grip strength was higher in TW compared to cisgender females (CW) in the long term. TW showed better performance in sports involving the upper body.

At least 2 years of postpubertal GAHT are necessary to achieve a significant reduction in the effects of male hormones on various physiological parameters. The scientific evidence regarding the impact of GAHT on physical performance is insufficient. Long-term studies are needed, incorporating new biomarkers and morphofunctional parameters, to allow for comparisons of athletic performance across different disciplines between TW and CW.