[Effect of elevated levels of natural radioactivity on the fecundity of male mice].

Male mice of the BALB/c strain were placed on the floor of a hut built at a site of Southwest France where the dose rate of gamma radiation amounts to about 10 mrad/h. Controls were kept near the radioactive site under comparable conditions. The doses of gamma rays received during a seven month period ranged from 0.1275 rad for the controls to 45 rad and 63 rad for the exposed animals. Due, possibly, to an effect on the libido exposure to 45 rad increased the fertility whereas the animals given 63 rad produced less offspring than the controls.