Transgender women and competitive sports: Considerations from Endocrinology.

Gender-affirming hormone therapy (GAHT) produces significant decreases in hematocrit, total serum testosterone, lean body mass, strength, and muscle area after 12 months.

• Changes were observed after 12 months of GAHT in transgender women
• Increases in fat mass were also observed alongside decreases in lean body mass
• Study design was a review of cross-sectional and longitudinal studies including transgender women (preferably athletes) undergoing GAHT

Grip strength remained higher in transgender women compared to cisgender females in the long term after GAHT.

• Grip strength was higher in TW compared to cisgender females (CW) in the long term
• This finding persisted despite significant reductions in other strength and body composition parameters
• This suggests that some male hormone-related physical advantages may persist beyond 12 months of GAHT

Transgender women showed better performance in sports involving the upper body compared to cisgender women.

• Upper body sports performance advantage was observed in TW relative to cisgender women (CW)
• This finding is consistent with the persistence of higher grip strength in TW after GAHT
• The finding suggests sport-category-specific considerations may be needed for inclusion policies

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 2-year threshold applies to postpubertal GAHT specifically
• This finding has implications for sports organizations setting eligibility criteria for transgender women in the female category
• The binary categorization of sports, influenced by the impact of sex hormones on physical performance, creates challenges for the inclusion of TW in the female category

The scientific evidence regarding the impact of GAHT on physical performance in transgender women is insufficient.

• Long-term studies are needed, incorporating new biomarkers and morphofunctional parameters
• Such studies are needed to allow for comparisons of athletic performance across different disciplines between TW and CW
• The review included cross-sectional and longitudinal studies that included TW preferably athletes undergoing GAHT
• The participation of transgender women in high-level competitive sports increases every year, making this evidence gap increasingly relevant