Predicting successful sperm retrieval in transfeminine adolescents after testicular biopsy

Increasing numbers of transgender adolescents are receiving gender-affirming treatments (GAT). Given GAT can impair reproductive function, clinical guidelines advise prior counselling regarding fertility preservation (FP). For transgender adults assigned male at birth, FP is usually achieved via a masturbatory sample and sperm cryopreservation. This is less straightforward in transgender adolescents, since they may not be developmentally ready to masturbate and/or masturbation may cause unacceptable gender dysphoria. Testicular biopsy represents an alternative method for sperm retrieval in these adolescents, but for those in early/mid puberty, it is difficult to predict whether sperm will be found. The purpose of this study was therefore to identify factors that predict successful sperm retrieval for cryopreservation via testicular biopsy.

A retrospective cohort study was undertaken at a tertiary-referral pediatric gender service. Subjects were included if they'd received a testicular biopsy in association with the commencement of GAT between 2010 and 2019. The primary outcome measure was successful sperm retrieval, and potential predictors included age, testicular volume and serum testosterone, LH and FSH levels.

Of 25 subjects who received a biopsy prior to starting any GAT, 17 had successful sperm retrieval. While age, testosterone, LH and FSH levels showed minimal differences, testicular volume was significantly higher in those with successful sperm retrieval, and a threshold of ≥ 10 mL showed 92% sensitivity and 71% specificity in predicting successful retrieval. An additional 6 patients received a biopsy after starting puberty suppression and before commencement of oestrogen, and one of these individuals had sperm successfully retrieved despite > 2 years of regular puberty suppression.

These findings suggest that testicular volume is most useful in predicting successful sperm retrieval following testicular biopsy in transgender adolescents and are likely to be of relevance to other young people undertaking FP, including those with cancer.