Fertility preservation is aimed at preserving the potential for genetic parenthood in adults or children at risk of sterility before undergoing anti-cancer treatments. The key reason for pursuing fertility protection is to restore personal autonomy to those who are unable to conceive. Impaired future fertility is another possible consequence of exposure to cancer therapies even for children. For boys who cannot produce mature sperm, harvesting and cryopreservation of testicular stem cells with the hope of future autologous transplantation or in vitro maturation represents potential methods of fertility preservation. Cancer survivors who did not preserve fertility and became sterile after chemo- or radiotherapy may agree to the use of donor gametes. Cancer survivors that have failed to preserve their gametes prior to sterilizing treatment might benefit in future of a type of stem cell research aimed at the creation in vitro of gametes derived from embryonic stem cells.