Transgender women and competitive sports: Considerations from Endocrinology.

María Miguélez González, Laura Cuadrado Clemente, Patricia Cabrera García, Mercedes Noval Font, Élida Alfaro Gandarillas, Marcelino Gómez Balaguer, Nieves Palacios Gil de Antuñano

Journal: Endocrinologia, diabetes y nutricion 2025;72(4):101539

PMID: 40185657

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Abstract

INTRODUCTION

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.

METHODS

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

RESULTS

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.

CONCLUSIONS

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.

Address: Servicio Endocrinología y Nutrición, Clínica EDOM, miembro GT-GIDSEEN, Gijón, Spain.; Unidad de Identidad de Género, Servicio Endocrinología y Nutrición, Fundación Jiménez Díaz, miembro de GT-GIDSEEN, Madrid, Spain. Electronic address: [email protected].; Unidad de Identidad de Género, Hospital Universitario de Canarias, miembro de GT-GIDSEEN, La Laguna, Santa Cruz de Tenerife, Madrid, Spain.; Servicio Endocrinología y Nutrición, Hospital Universitario Son Espases, Palma de Mallorca, Balearic Islands, Spain.; Directora del seminario Mujer y Deporte, Facultad de Ciencias de la Actividad Física y Deporte, Universidad Politécnica, Madrid, Spain.; Fundación FÍSABIO Valencia, Unidad de Identidad de Género, Hospital Universitario Doctor Peset, Valencia, Spain.; Servicio de Medicina, Endocrinología y Nutrición, Centro de Medicina del Deporte, Subdirección General de Ciencias del Deporte, Consejo Superior de Deportes, coordinadora del GT-GENEFSEEN, Madrid, Spain.

DOI: 10.1016/j.endien.2025.101539

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MeSH Terms: Humans, Female, Transgender Persons, Male, Athletic Performance, Gender-Affirming Procedures, Sports, Testosterone, Hormone Replacement Therapy, Cross-Sectional Studies, Athletes, Body Composition