Azoospermia or Severe Oligozoospermia

This is a pilot clinical trial to evaluate the feasibility and outcome of autologous transplantation of immature testicular tissue cryopreserved during childhood as a method of fertility preservation for prepubertal boys in case of gonadotoxic therapies. Freezing of immature testicular tissue is performed since the early 2000s and a number of our patients have now reached reproductive age. In case of childwish and azoospermia in adulthood, surgical sperm retrieval is planned and if unsucessful transplantation of the patient's own cryopreserved tissue will be performed during the same surgical intervention as a fertility restoration method.