Radiation Effects on the Egg and Sperm
Genetic effects (those that are seen in the children of the exposed person) are possible when the egg or sperm is irradiated; however, this effect has not been demonstrated in humans. The concern of most patients is whether radiation exposure to the egg or sperm will result in birth defects. The risk from radiation exposure to the egg or sperm prior to conception has been studied in two large populations. In one study, thousands of patients who were exposed to radiation in Hiroshima and Nagasaki and had families were studied for the incidence of genetic disease and other reproductive effects. After 50 years of study on this population, there has been no demonstrable increase in genetic disease found. What was learned is that the risk is extremely small and that you need very large populations to demonstrate this risk. In other words, the risk from the radiation is too small to be detected because of the spontaneous incidence of defects and the hereditary component of mutations that may affect future generations.
Similarly, the National Cancer Institute has studied men whose testes were exposed during radiation therapy as well as men who received chemotherapy with drugs and chemicals. There are now several thousand patients who have survived cancer which occurred in childhood, adolescence, or early adulthood. Families of these individuals also have not demonstrated an increase in birth defects or miscarriage.
External beam radiation therapy of the pelvis, hip, femur (upper long bone of the leg), bladder, and prostate may expose the testes or ovaries to radiation. While it is possible to shield the testes for some of these radiation procedures, the radiation dose from scattered radiation could still be quite high. With high doses to the testes or the ovaries, the main complication is temporary or permanent sterility. For those patients who remain fertile after therapy, the reproductive risks are not increased significantly. In other words, the risk of birth defects in the next generation for those who remain fertile and able to conceive is quite low.
Studies of the atomic bomb survivors indicate that even in the high-exposure group there is not an increased incidence of chromosome abnormalities or genetic disease in the next generation. That is also the case for studies from the National Cancer Institute, which indicate that for patients who had cancer and received chemotherapy and radiation, there was no increased incidence in genetic disease or birth defects in the next generation, although the patients did have problems with fertility.