Recent advances: fertility preservation and fertility restoration options for males and females.

Fertility preservation is the process of saving gametes, embryos, gonadal tissues and/or gonadal cells for individuals who are at risk of infertility due to disease, medical treatments, age, genetics, or other circumstances. Adult patients have the options to preserve eggs, sperm, or embryos that can be used in the future to produce biologically related offspring with assisted reproductive technologies. These options are not available to all adults or to children who are not yet producing mature eggs or sperm. Gonadal cells/tissues have been frozen for several thousands of those patients worldwide with anticipation that new reproductive technologies will be available in the future. Therefore, the fertility preservation medical and research communities are obligated to responsibly develop next-generation reproductive technologies and translate them into clinical practice. We briefly describe standard options to preserve and restore fertility, but the emphasis of this review is on experimental options, including an assessment of readiness for translation to the human fertility clinic.