Men who drink a lot of alcohol may have a higher chance of having children with physical or mental problems. Doctors have long been aware that women alcoholics may give birth to defective babies. However, scientists have recently discovered that alcoholism in men may be responsible for birth defects too. Large quantities of alcohol may affect the quality of the father's genes. This genetic change may cause a child to be born defective in some way. Scientists are not sure how this happens. But the statistics of the study seem to leave little doubt that it can happen.