Paul considered becoming a Lutheran minister like two of his brothers[10] (Jerrold has a doctorate in counseling and attended Princeton Seminary; David pastors Trinity Lutheran Church in Grand Rapids, Michigan).[7][13] Instead he decided to pursue a medical degree at Duke University School of Medicine in Durham, North Carolina, attaining it in 1961. He interned and began residency training, both in internal medicine, at Henry Ford Hospital in Detroit (1961–1962); Carol meanwhile ran a dance school in their basement and raised collies.
The medical training was soon interrupted when he received a draft notice and entered the U.S. Air Force during the Cuban Missile Crisis. He remained in the military during the early years of the Vietnam War. He served active duty as a flight surgeon from 1963 to 1965, attending to the ear, nose, and throat problems of pilots in South Korea, Iran, Ethiopia, and Turkey, but was never sent to Vietnam. Based out of Kelly Air Force Base in San Antonio, Paul achieved the rank of captain and obtained his private pilot's license. The experience of performing physicals on helicopter pilot candidates, at a time when he saw many copters being shot down, deeply affected Paul; he later considered his indirect association with Vietnam as a catalyst for his rejection of interventionist foreign policy.
Paul received a higher wage from the Air Force than during his initial residency, $700 per month; he joked that he was "fantastically rich". While in San Antonio, he also moonlighted three nights a week in a local church hospital's emergency room for $3 per hour, and became involved with Barry Goldwater's presidential campaign. He then served in the Air National Guard while completing his residency (1965–1968), having switched to ob/gyn at the University of Pittsburgh. His residency research into causes of pregnancy toxemia was subsequently published in the journal Obstetrics and Gynecology.
He moved to Surfside Beach, Texas, on July 3, 1968, and eventually delivered more than 4,000 babies. Assuming the practice of a retiring doctor in Lake Jackson, Texas, in a single day, Paul became the only ob/gyn doctor in Brazoria County, reportedly delivering 40–50 babies a month and frequently busy with surgery. His practice refused Medicare and Medicaid payments; he worked pro bono, arranged discounted or custom-payment plans for needy patients, or otherwise "just took care of them".
