Purpose <p>Transgender men (TGM) are individuals who identify as males but were assigned female sex at birth. Gender-affirming testosterone therapy (GATT) is used to induce virilization, and its effects on fertility are discussed. To provide TGM with complete fertility counseling, we synthesized data concerning the impact of GATT on ovarian reserve and oocyte quality.</p> Methods <p>We conducted a narrative review of published data on the ovarian and oocyte features induced by GATT in TGM.</p> Results <p>Data on ovarian morphology and histology showed a normal proportion of primordial, primary, pre-antral, and antral follicles, and a significantly higher number of atretic and cystic follicles. Additionally, ovaries exhibited diffuse ovarian stromal hyperplasia and a thicker ovarian cortex, tunica albuginea, and basal membrane. No impact on ovarian reserve was observed. Oocyte quality following ovarian stimulation did not appear to be impaired and led to the birth of healthy offspring.</p> Conclusion <p>These findings may reassure transgender patients and their care providers that satisfactory reproductive outcomes are possible, even if GATT has already been initiated. However, further investigation is needed to assess the reversibility and functional impact of these changes on ovarian folliculogenesis, ART success rates, pregnancy, and child health.</p>