Effects of estrogen on spermatogenesis in transgender women.

OBJECTIVE To characterize spermatogenesis in the estrogenized transgender patient. MATERIALS AND METHODS This is a retrospective, single-center, cross-sectional study. Seventy-two transgender women underwent gender-affirming orchiectomy between May 2015 and January 2017. All were on long-term (>1 year) cross-sex hormonal therapy prior to orchiectomy. Patient data were obtained via chart review. Histologic analysis was performed by a pathology resident under the supervision of a genitourinary pathologist. The main outcome is histologic presence of germ cells and presence of spermatids (a proxy for preserved spermatogenesis) in orchiectomy specimens. RESULTS There were 141 pathologic specimens available for analysis. Germ cells were present in 114 out of 141 (81%) testicles. Spermatids were present in 57 (40%) testicles. Presence of germ cells was associated with older age (43 vs 35 years, P = .007) and increased testicular weight (28.6 g vs 19.3 g, P <.001). Presence of spermatids was associated with increased weight (31.5 g vs 23.3 g, P <.001) and volume (20.3 mL vs 12.6 mL, P <.001). There was a linear correlation between testis volume and preserved spermatogenesis (Pearson's r = 0.448, P <.001). CONCLUSION Despite long-term hormone therapy, the majority (80%) of transgender women have germ cells present in the testicle. Spermatogenesis is preserved in approximately 40% of these individuals. Duration of hormonal therapy did not affect the degree of preservation of germ cells or spermatogenesis but starting hormonal treatment at a younger age may be associated with decreased germ cells in the testicle. Volume of testicles predict presence of preserved spermatogenesis.