Rohayem J, Haffner D, Cremers JF, et al. - Researchers conducted a prospective cohort study with the aim to determine if males with the rare lysosomal storage disease infantile nephropathic cystinosis (INC) have a chance of biological fatherhood. In this cross-sectional investigation, 18 male patients with INC were assessed for their endocrine and spermatogenic testicular function. Most patients showed high adherence to cysteamine treatment. Normal ranges of testicular volumes and testosterone levels were recorded in all, except two and three older patients, respectively. All individuals aged ≥ 20 years had serum LH levels above the normal range. In histological examination, fully preserved spermatogenesis was identified in the centre of their testes, but also with tubular atrophy and lysosomal overload in Sertoli and Leydig cells of the testicular periphery. Overall findings suggest cryostorage of semen to be an option for nearly 20% of young males with INC, with surgical sperm retrieval from the centre of the testes providing additional opportunities for fatherhood.