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83 HISTOLOGICAL STUDY ON THE INFLUENCE OF PUBERTY SUPPRESSION AND HORMONAL TREATMENT ON DEVELOPING GERM CELLS 6 Main results and the role of chance: Mature spermatozoa were encountered in 4.7% of orchiectomy specimens, all from transgender women who had initiated medical treatment in Tanner stage 4 or higher. 88.3% of the study sample only contained immature germ cells (round spermatids, spermatocytes, or spermatogonia, as most advanced germ cell type). In 7.0%a complete absence of germcells was observed,all these samples were from transgender women who had initiated medical treatment in adulthood. Cessation of hormonal treatment prior to gGAS did not affect the presence of germ cells or their maturation stage, nor was there an effect of the duration of hormonal treatment prior to gGAS. Limitations, reasons for caution: Since data on serum hormone levels on the day of gGAS were not available, we were unable to verify if the transgender women who were asked to temporarily stop hormonal treatment four weeks prior to surgery actually did so, and if people with full spermatogenesis were compliant to treatment. Wider implications of the findings: There may still be options for fertility preservation in orchiectomy specimens obtained during gGAS since a small percentage of transgender women had full spermatogenesis, which could enable cryopreservation of mature spermatozoa via a testicular sperm extraction procedure. Furthermore, the vast majority still had immature germ cells, which could enable cryopreservation of testicular tissue harboring spermatogonial stem cells. If maturation techniques like in vitro spermatogenesis become available in the future, harvesting germ cells from orchiectomy specimens might be a promising option for those who are otherwise unable to have biological children.