Lierman S, Tolpe A, De Croo I, et al. - Via performing this cross-sectional study, rserachers sought to report on the feasibility of in vitro maturation of ovarian tissue oocytes for fertility preservation in transgender men on testosterone treatment. Among 83 enrolled transgender men, interventions included in vitro maturation of cumulus-oocyte complexes (COCs) harvested at the time of gender confirmation surgery, and fertilization through intracytoplasmic sperm injection. Testosterone treatment was provided to all participants for a median of 83 weeks. Collection of a total of 1,903 COCs was done. They identified in vitro maturation rate of 23.8%, vitrification rate of 21.5%, and survival rate after warming of 72.6% (n = 151). In 139 oocytes, intracytoplasmic sperm injection was conducted. Normal fertilized oocyte rate was 34.5%, and 25 (52.1%) embryos reached day 3. Overall findings revealed low developmental capacity in ovarian tissue oocytes matured in vitro in transgender men, when obtained under testosterone treatment.