Abstract
Present findings confirm and extend previous observations that x-irradiation during certain stages of prenatal development results in testicular injury and infertility in the male rat. The effects were particularly marked in the offspring of rats irradiated on the 18th day of pregnancy. These rats also showed in addition to testes injury a significant reduction in seminal vesicle weight. Testicular injury also occurred in the offspring of rats irradiated on the 14th day of pregnancy but was less marked than in the 18-day series. No abnormalities in testicular function or morphology were observed in the offspring of rats irradiated on the 10th day of pregnancy.