American scientists have discovered defects in mice bred using cultured embryos. The adult mice had behavioural disorders, which the scientists believe came from altered gene function caused by storage.
Dr Ted Abel, from the University of Pennsylvania, said: "Our findings suggest that a special effort should be made to minimise the effect of culture on pre-implantation embryos. Decreasing the length of time between fertilisation and implantation."
Although the scientists say that the problem might not occur with human embryos, the risk needed to be minimised and more research carried out to see what effect storage has on human embryos.
