Fertility preservation. The treatment used to treat cancer or other non-cancer diseases have improved the prognosis of these pathologies. However, these treatments (chemotherapy, radiotherapy or even surgery) have a toxicity on the ovary or on the testicle with consequently a decrease or an arrest of the production of mature oocyte or spermatozoa. Fertility preservation uses freezing procedures of gametes (oocytes, spermatozoa), embryos or germinal tissues (ovary or testicle) in order to restore the fertility of cured patients. The French national sperm banking network (CECOS) is a national network of assisted reproductive technology centers that manage, in a coordinated manner, all of these fertility preservation techniques.