Live births from frozen human semen stored for 40 years

摘要

Low temperature storage in liquid nitrogen is thought to maintain the viability of cells almost indefinitely because reactions that require molecular motion and/or activation do not occur at -196degC. The adverse effects of background radiation during storage appear to be negligible since exposure of mouse embryos to the equivalent to 2,000 years of background radiation did not have a detectable effect on their viability [1]. Two clinical reports have been published on the successful use of human semen stored for longer than 20 years. Live births have been reported from in vitro fertilization with semen stored for 21 years [2] and from IUI with semen stored for 28 years [3]. In farm animal species, Salamon et al. [4] reported that ram semen maintained its fertility after 35 years of storage. Here we report the birth of twins from in vitro fertilization using semen stored for approximately 40 years.