Storage and disposal of embryos and gametes

Freezing of sperm and preimplantation embryos is a technique used routinely in livestock industries, laboratory animal breeding, and genetic conservation, and more recently it has been used to aid the conservation of endangered species. In human infertility, freezing sperm ensures the safe, effective use of sperm for insemination. It also enables men who are about to undergo treatment which affects sperm production–involving drugs, chemotherapy, or radiotherapy–to store sperm for later use. Embryos are frozen for patients undergoing in vitro fertilisation, either to improve the chance of conception or to allow for planned use in the future. Freezing spare embryos allows replacement of an optimum number to avoid the risk of multiple birth and avoids the waste of discarding potentially viable embryos produced as a result of superovulation.1 But the ability to freeze embryos has presented us with important dilemmas, especially over the question of their future use or misuse. Legal disputes can arise when partners separate or divorce or when one or both partners die. A recent survey of attitudes to the posthumous use and storage of sperm and embryos reported in this issue by Corrigan et al (p 24) illustrates the confusion about such situations …