John Romulus Brinkley (later John Richard Brinkley; July 8, 1885 – May 26, 1942) was an American quack who fraudulently claimed to be a medical doctor. He had no legitimate medical education and bought his medical degree from a "diploma mill". Brinkley became known as the "goat-gland doctor" after he achieved national fame, international notoriety and great wealth through the xenotransplantation of goat testicles into humans. Although initially Brinkley promoted this procedure as a means of curing male impotence, eventually he claimed that the technique was a virtual panacea for a wide range of male ailments. He operated clinics and hospitals in several states, and despite the fact that almost from the beginning, detractors and critics in the medical community thoroughly discredited his methods, he was able to continue his activities for almost two decades.