The first time the United States instituted a military draft was between 1917 and 1920. With another world war looming, President Franklin Roosevelt signed the Selective Training and Service Act of 1940 to launch another draft. Young males were classified as to their suitability for military service from 1-A (available for unrestricted military service) down to 4-F (not acceptable for military service).
A 4-F rating resulted from unfitness for physical, mental, or moral reasons. Thirty percent of American men who registered for military service during the Second World War received a 4-F classification, usually for muscle or bone irregularities, hearing or circulatory ailments, mental problems, hernias, or syphilis. While some men (such as Doc Daneeka, who tried to classify himself 4-F) craved the rating to avoid having to fight, young women often avoided dating such men for patriotic or imagined health deficiency reasons.