Born in Scotland, Irwin Thompson spent most of his childhood in wartime Glasgow, dealing with bombings and food rationing. He started medical school at the age of 17; he would eventually specialize in obstetrics/gynecology (OB/GYN). After spending some time in the United States, he was starting a PhD program in Sweden when the U.S. Army drafted him. Thompson would serve three years (1968-71) with the U.S. Army Medical Corps at a hospital in Germany, treating military families.