Freezing testicular tissue of prepubertal boys is a method for preserving spermatogonial stem cells (SSCs) in case of imminent gonadotoxic treatment during childhood. In case of total azoospermia in adulthood and presence of a childwish, the investigators intend to perform the first in men autologous testicular tissue transplantation to restore fertility.

Freezing testicular tissue of prepubertal boys is a method for preserving spermatogonial stem cells (SSCs). In 2002, the University hospital in Brussels (UZB) was the first hospital worldwide to offer testicular tissue cryobanking for fertility preservation in boys and ado-lescents. Since then, several other centers in Europe and USA have implemented similar fertility preservation programs. However, up till now, autologous transplantations of cryopreserved testicular tissue have not been performed yet. As soon as a patient returns to the Centre for Reproductive Medicine at UZB with the request to transplant the preserved testicular tissue, the investigators will first analyse semen and blood. If spermatozoa are found in their semen, men can immediately enroll in standard care for natural conception, intra-uterine insemination (IUI), in-vitro fertilization (IVF) or intra-cytoplasmic injection (ICSI). However, in case no spermatozoa are found in the ejaculate the investigators intend to propose and eventually perform autologous testicular tissue transplantation with the primary objective being to restore spermatogenesis and fertility.