Germ cell transplantation.

Transplantation of germ cells leads to restoration of spermatogenesis from spermatogonial stem cells. The original description of germ cell transplantation in 1994 has led to new approaches to explore many basic aspects of spermatogonial physiology. Combining germ cell transplantation with culture and cryopreservation of spermatogonia opens new pathways for genetic engineering and conservation of livestock. In addition, autologous transfer of spermatogonia might be used as an approach for fertility preservation in oncological patients. This review summarises the history of germ cell transplantation and presents an outlook on future research on spermatogonial stem cells.