Study of 214 natal males treated with GnRH agonists (with/without estrogen): full spermatogenesis in only 4.7%, all of whom started blockers at Tanner stage 4+; those blocked at Tanner 2/3 then given estrogen showed only immature germ cells – primary evidence that early blockade plus cross-sex hormones forecloses sperm production, consistent with guideline fertility-counseling requirements.
only 4.7% [had] full spermatogenesis; all [such] initiated [treatment] at Tanner stage 4 or later
Study of 214 natal males treated with GnRH agonists (with/without estrogen): full spermatogenesis in only 4.7%, all of whom started blockers at Tanner stage 4+; those blocked at Tanner 2/3 then given estrogen showed only immature germ cells – primary evidence that early blockade plus cross-sex hormones forecloses sperm production, consistent with guideline fertility-counseling requirements. Cohort study (n=214). See also review PMC10371879: GnRHa treatment yields scarce gamete maturation.