Ernst Gräfenberg was a physician and researcher who studied sexology, the study of human sexuality, in both Germany and the United States during the first half of the twentieth century. Gräfenberg researched the use of intrauterine devices as a form of contraception, and he developed the Gräfenberg ring. The Gräfenberg ring was one of the first intrauterine devices that effectively prevented pregnancy without causing infection, and it became the forerunner of all modern intrauterine devices, or IUDs. Gräfenberg also studied the role of the urethra in female orgasm. He was one of the first researchers to discuss female pleasure in a scientific manner, and, more specifically, he was one of the first to write about the erogenous zone on the anterior vaginal wall, colloquially called the G-spot. Through the technology he developed and the ideas he proposed, Gräfenberg advanced knowledge of female anatomy, pleasure, and reproduction, enabling researchers and professionals to better understand and cater to females’ reproductive and sexual needs.