[Fertility preservation in persons with gender incongruence and male-assigned sex at birth].

According to current guidelines, patients with gender incongruence seeking treatment must receive appropriate education and counselling from healthcare professionals on the various options for fertility preservation. Gender-affirming hormonal treatment leads in persons assigned male at birth to a reduction of LH, FSH, and testosterone, which is associated with a regression of spermatogenesis (up to complete loss) and subsequent testicular atrophy. Individuals starting gender-affirming hormonal treatment after having experienced male puberty may provide an ejaculate sample for sperm cryopreservation. In cases where no sperm is detected in the ejaculate due to gender-affirming hormonal treatment, or if the sampling of ejaculate is no longer possible or causes excessive psychological distress, (microsurgical) testicular sperm extraction [(m)TESE] should be offered. Electroejaculation under anaesthesia is rarely effective, as hormonal treatment impairs spermatogenesis. Similarly, microsurgical epididymal sperm aspiration (MESA) is not typically effective for the same reason. If adolescents with gender incongruence undergo puberty blockade and/or gender-affirming hormonal treatment at an early stage of puberty (possible from Tanner stage 2), this prevents the maturation of spermatogonial stem cells into mature sperm. Puberty blockade with GnRH reduces the secretion of LH and FSH by the pituitary gland, which, in turn, suppresses the production of testosterone in the Leydig cells and the stimulation of spermatogenesis in the testicles. In such cases, the cryopreservation of spermatogonial stem cells is possible, similar to how it is offered in some countries for peri-pubertal patients prior to necessary germ cell-toxic treatments. In Germany, there is a relevant network (Androprotect), which was founded in Münster in 2012. Via Androprotect, this procedure is also offered for adolescent individuals with gender incongruence. This approach is considered experimental as no established treatment exists for the refertilisation of affected adults at a later stage, although several procedures for in-vitro sperm maturation and tissue transplantation are under development. The care of patients with gender incongruence should include individual counselling provided by experienced professionals in an interdisciplinary treatment team. Individual treatment approaches should be offered to facilitate shared decision-making (based on informed consent) to ensure that each individual can make an informed and appropriate decision regarding fertility preservation.