Oocyte freezing: here to stay?

Oocyte freezing is an established technology but, in contrast to embryo freezing, it has very limited application in clinical IVF programmes. Is there a chance that oocyte freezing will become an integrated routine in assisted reproductive technology? The delicate cytological architecture of the oocyte with a cold-sensitive spindle and a hardening zona have made the frozen oocyte 'unwanted' in assisted reproductive technology. Nevertheless, empirical improvements in freezing protocols and the use of ICSI for fertilization have led to an increasing number of live births. This mitigates against a simple ban on oocyte freezing. While efficiency of oocyte freezing can certainly be further improved by basic research, it is clear that there are humanitarian reasons for considering oocyte freezing as a future fully utilized assisted reproductive technology. The storage of the female genome as a particulate entity can provide an alternative in case of moral, ethical, legal or religious concerns about embryo freezing. Oocyte freezing can also offer hope for oocyte donation and preservation of fertility for women facing ovarian loss. The message is one of cautious optimism when looking for a place for oocyte freezing in routine assisted reproductive technology.