Reproductive desires and outcomes of transgender and gender diverse adolescents and young adults: to preserve or not to preserve

This thesis examines fertility in transgender and gender‑diverse (TGD) people in the context of gender‑affirming care. Puberty suppression with GnRH analogues and gender‑affirming hormone treatment (GAHT) can alter reproductive options. The first part summarises current knowledge on reproductive desires, fertility counselling, fertility preservation, and the histological impact of treatment on gonads, and distils this into a practical counselling guide. Although international guidelines recommend fertility counselling before puberty suppression or GAHT, counselling is not universally provided. In adolescents, counselling rates are relatively high but FP utilisation is very low. Invasive procedures, cost, and worries about delaying GAHT are major barriers. Among adults, counselling is less consistently offered, particularly where FP is not reimbursed, and there is a persistent discrepancy between interest in FP and actual uptake. For individuals with ovaries, oocyte cryopreservation is feasible both before and after testosterone exposure. Available data show no clear negative association between testosterone duration and oocyte yield, and several pregnancies and live births have been reported from oocytes collected after prolonged testosterone use. For individuals with testes, semen quality is often suboptimal even before treatment. Under oestradiol plus anti‑androgens, spermatogenesis is commonly severely impaired or absent; recovery after cessation of GAHT is possible but variable and poorly characterised. TESE provides an additional option for those unable to masturbate, but success depends on adequate pubertal development. The second part of the thesis presents original data on reproductive wishes and FP outcomes in TGD adolescents and transmasculine young adults. In a multicentre adolescent cohort at the start of puberty suppression or GAHT, about half expressed a desire for future children, whereas genetic parenthood was less central and many anticipated that their wishes might evolve. None of the transmasculine adolescents pursued FP; about one‑fifth of transfeminine adolescents did, mainly via semen cryopreservation and TESE, with often low post‑thaw semen quality. Decisional conflict about fertility choices was moderate to high. These findings support integrating structured, mandatory fertility counselling into adolescent gender‑affirming care, timed before GAHT for transmasculine youth and before puberty suppression or GAHT for transfeminine youth, and offering TESE where masturbation is not acceptable. Among transmasculine young adults followed for two years after fertility counselling, a minority undertook oocyte or cortex cryopreservation or pregnancy, while some proceeded to ovariectomy. One in five changed their reproductive intentions over this relatively short period, underscoring the dynamic nature of reproductive goals even after transition. In the largest cohort to date on oocyte cryopreservation following testosterone and/or puberty suppression, neither testosterone duration, timing of cessation, nor prior puberty suppression predicted oocyte yield, reinforcing the feasibility of FP after prolonged testosterone exposure. However, long‑term effects on fertilisation, embryo development and offspring health remain unknown. The final part focuses on transfeminine adolescents considering FP before or during early puberty suppression. Many chose to delay suppression to allow spermatogenesis to develop sufficiently for FP; most selected TESE over semen cryopreservation. This delay often resulted in distressing pubertal changes, perceived as significant suffering by adolescents and parents, though many later expressed relief at having preserved gametes. Qualitative work shows that while the TESE procedure and recovery seldom worsened gender dysphoria, the waiting period for spermatogenesis was psychologically burdensome. These findings underline the need for robust mental health support and close multidisciplinary collaboration with families when offering FP in early puberty, and for refining clinical markers (e.g. testicular volume and hormone levels) to optimise timing and minimise unwanted physical changes. Overall, the thesis argues for embedding fertility considerations throughout gender‑affirming care, using longitudinal, patient‑centred counselling, improving access to FP, and prioritising research on long‑term fertility and offspring outcomes and on innovative techniques such as effective IVM.