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.