[Relationship between age of the male and spontaneous or radiation induced prenatal mortality in mice].

Control and X-irradiated male mice from the BALB/c strain, three or twelve months old, have been mated with 3 months old virgin females from the same strain. Dissection of the females on the seventeenth day after the beginning of the mating has shown that the preimplantation is increased when the males are twelve months old whereas exposure to ionizing radiations enhances only the postimplantation loss. It is possible that the increase in preimplantation loss results from some changes in the vitality or fertilizing capacity of the spermatozoa.