Fertility preservation in trans women is a crucial but thus far neglected component in the gender confirming treatment in Germany. It is difficult for trans women to access reproductive health care because centers offering treatment, psychological guidance, gender confirming surgery, as well as reproductive health services are scarce in Germany. Legal, social, or financial issues as well as individual patient comorbidities prevent trans women from receiving appropriate counselling. This review provides an overview on options of fertility preservation in trans women. We consider recent publications on testicular regression at the time of gender confirming surgery demonstrating presence of sperm or at least spermatogonia in the majority of tissues. This may open options for cryopreservation of sperm or testicular stem cells in trans women even at the final stage of transition. Hence, standardized urological procedures (i.e., sperm cryopreservation after masturbation or sperm extraction from the testicular tissue) and experimental approaches (cryopreservation of testicular tissue with undifferentiated spermatogonia) can be offered best at the initiation but also during the gender confirming process. However, counselling early in the gender confirming process increases the chances of fertility preservation because gender confirming hormone therapy has an impact on spermatogenesis.

The calcium-activated potassium channel 3.1 (K Ca 3.1) is overexpressed in many tumor entities and has predictive power concerning disease progression and outcome. Imaging of the K Ca 3.1 channel in vivo using a radiotracer for positron emission tomography (PET) could therefore establish a potentially powerful diagnostic tool. Senicapoc shows high affinity and excellent selectivity toward the K Ca 3.1 channel. We have successfully pursued the synthesis of the 18 F-labeled derivative [ 18 F]3 of senicapoc using the prosthetic group approach with 1-azido-2-[ 18 F]fluoroethane ([ 18 F]6) in a "click" reaction. The biological activity of the new PET tracer was evaluated in vitro and in vivo. Inhibition of the K Ca 3.1 channel by 3 was demonstrated by patch clamp experiments and the binding pose was analyzed by docking studies. In mouse and human serum, [ 18 F]3 was stable for at least one halflife of [ 18 F]fluorine. Biodistribution experiments in wild-type mice were promising,showing rapid and predominantly renal excretion. An in vivo study using A549based tumor-bearing mice was performed. The tumor signal could be delineated and image analysis showed a tumor-to-muscle ratio of 1.47 ± 0.24. The approach using 1-azido-2-[ 18 F]fluoroethane seems to be a good general strategy to achieve

Background: Anti-Müllerian hormone and inhibin B are produced by Sertoli cells. Anti-Müllerian hormone secretion indicates an immature Sertoli cell state. Inhibin B serves as a marker of male fertility. Identification of markers reflecting the presence of germ cells is of particular relevance in trans persons undergoing gender-affirming hormone therapy in order to offer individualized fertility preservation methods. Objectives: Serum and intratesticular inhibin B and anti-Müllerian hormone values were assessed and related to clinical features, laboratory values, and germ cell numbers. Materials and methods: Twenty-two trans women from three clinics were included. As gender-affirming hormone therapy, 10-12.5 mg of cyproterone acetate plus estrogens were administered. Height, weight, age, medication, and treatment duration were inquired by questionnaires. Serum luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol were measured by immuno-assays. Serum and intratesticular inhibin B and anti-Müllerian hormone were measured by commercially available ELISAs. Spermatogonia were quantified as spermatogonia per cubic millimeter testicular tissue applying a morphometric analysis of two independent testicular crosssections per individual after MAGEA4 immunostaining. Results: Patients with high inhibin B levels presented with a higher number of spermatogonia (*p < 0.05). Furthermore, mean serum inhibin B was associated with low age (*p < 0.05), low follicle-stimulating hormone (*p < 0.05), and low testosterone (*p < 0.05). Serum anti-Müllerian hormone, however, was not related to spermatogonial numbers. It correlated with high testosterone (*p < 0.05) and high follicle-stimulating hormone (*p < 0.05) only. High intratesticular inhibin B was accompanied by high luteinizing hormone (*p < 0.05), high follicle-stimulating hormone (**p < 0.01), and high testosterone levels (**p < 0.01

Objective Germ cells of transwomen are affected by gender affirming hormone therapy (GAHT). Fertility will be lost after surgical intervention, thereby fertility preservation becomes an increasingly important topic. We investigated if the absolute number of spermatogonia in transwomen is comparable at the time of gender affirming surgery (GAS) to that in prepubertal boys. Methods We carried out a retrospective study of testicular tissues from 25 selected subjects, which had undergone a comparable sex hormone therapy regimen using cyproterone acetate (10 or 12.5 mg) and estrogens. As controls, testicular biopsies of 5 cisgender adult men (aged 35 – 48 years) and 5 pre-/pubertal boys (5 – 14 years) were included. Testicular tissues were immuno-histochemically stained for MAGE A4 positive cells, the most advanced germ cell type. The number of spermatogonia per area were assessed. Clinical values and serum hormone values for FSH, LH, testosterone, free testosterone, estradiol and prolactin were determined on the day of GAS for correlation analyses. Results Round spermatids were the most advanced germ cell type in 3 subjects, 5 had an arrest at spermatocyte stage while 17 showed a spermatogonial arrest. On average, testicular tissues of transwomen contained 25.15 spermatogonia/mm3, a number that was significantly reduced com-pared to the two control groups (P < 0.01, adult 80.65 spermatogonia/mm3, pre-/pubertal boys 78.55 sper-matogonia/mm3). Linear regression analysis revealed that testes with higher weight and high LH contained more spermatogonia. Conclusion Irrespective of treatment dose or duration spermatogenesis was impaired. Spermatogonial numbers were significantly reduced for transwomen compared to the control groups.