Ovarian cryopreservation presents a valid alternative to egg freezing in some circumstances. The possibility to store oocytes for a later use is also an important consideration for women who choose to postpone motherhood for personal or professional reasons. Any newly developed protocol should consider the biochemical and physical properties of the oocyte. In addition to surviving the cryopreservation/warming process, the oocyte needs to maintain competence to fertilize and develop in vitro to the appropriate embryonic stage without any structural alterations. Slow cooling protocol is characterized by a slow decreasing temperature rate. Several mathematical models define an optimal curve applicable to oocytes since the freezing rate is vital to achieve sufficient and progressive dehydration, and thereby minimize the potential of intracellular ice formation. During fresh cycles only a few oocytes can be inseminated; therefore, cryopreservation is the only option to avoid wastage of surplus eggs and consequent repeated ovarian stimulation.

Cytogenetic abnormalities of the human oocyte, as described by Pellestor, are remarkably common and there appears to be a multifactorial effect of maternal ageing. Aneuploid embryos are common following in vitro fertilization (IVF), even in unstimulated cycles. Egg freezing has proved to be technically much more difficult than embryo freezing. Ovarian failure is an untreatable condition but the opportunity for pregnancy can be restored by egg donation. Success rates are high and are maintained with increasing age. If the uterus cannot support a pregnancy, for example because of fibroids, or if the potential mother is too unfit for pregnancy, surrogacy will be required. In reviewing the uses of assisted reproduction, some 'abuses' have been revealed. The infertile couples seeking help can be desperate for treatment and therefore be vulnerable to suggestion. Reproductive tourism is burgeoning, driven by women's needs for treatment but also by commercial interests.