[Fertility preservation before puberty: from mice to men]

Malignant tumors account for 1% of childhood cancers. The incidence is to the order of 122 cases per million children. The five-year survival after cancer before the age of 16years has improved from 50 to 80% in 40years. Assessment of potential for preservation of fertility should thus be a systematic element of care for children treated for a malignant tumor (high-dose chemotherapy with alkylizing agents, radiation therapy including the gonads) or those receiving hematopoietic stem cell grafts for malignant or benign disease (sickle-cell anemia, immune deficit). Among the techniques proposed, cryopreservation of ovarian tissue appears to be the most promising, or perhaps the only one available before puberty with encouraging result. Nevertheless the uncertainties, or even risks, related to these treatments, should not be neglected.