ABSTRACT
Cryopreservation is the freezing of sperm or embryos and their storage in liquid nitrogen, for thawing and transfer at a later date. The Human Fertilisation and Embryology Authority (HFEA) does not allow frozen eggs to be used for treatment. Some embryos do not survive being frozen, but the suggestion that abnormal embryos are more likely to be killed by freezing has yet to be proven. The HFEA makes exceptions where a couple want to have another child using the same donor who provided gametes used in conceiving a previous child. Embryos can only be exported overseas with the written consent of the provider of those gametes under a special direction from the HFEA and similar information as for the import of gametes or embryos. The HFEA would prefer that sperm and eggs were donated as a voluntary gift and are looking for ways to promote a culture of altruism.
