By all means, there should be no children when either mother or father suffers from such diseases as tuberculosis, gonorrhea, syphilis, cancer, epilepsy, insanity, drunkenness and mental disorders. In the case of the mother, heart disease, kidney trouble and pelvic deformities are also a serious bar to childbearing No more children should be born when the parents, though healthy themselves, find that their children are physically or mentally defective.