Harold Delf Gillies performed one of the first sexual reassignment surgeries, termed gender affirmation surgeries as of 2022, on record in 1946 in London, England. He also practiced modern plastic surgery and helped distinguish it as a new branch of medicine in London, England, starting in the early 1900s. Gillies’s work focused initially on facial reconstructive surgery, particularly during both World War I and World War II. Gillies created newer and more efficient techniques that later became standard procedures for reconstructive and cosmetic surgeries. Gillies, along with two members in his practice, standardized over 11,000 techniques, and beginning in 1946, he performed one of the first successful phalloplasties on a transgender man, where he formed a new penis from the patient’s existing skin and tissue.

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.

Emil von Behring researched treatments for the common childhood disease diphtheria in Germany in the 1890s and early 1900s. Diphtheria is a lethal disease that infected approximately 40,000 people in Germany between 1886 and 1888 with a general mortality rate of twenty-five percent. Behring investigated treatment of diphtheria using serum therapy, which is an alternative to vaccination that uses protective agents from other people’s blood to defend a patient against disease. Behring termed those protective agents antitoxins. He received the first Nobel Prize in Physiology or Medicine for his work on serum therapy, which was one of the first Nobel Prizes given in the field of immunology. Additionally, Behring researched active vaccination as another way to protect patients from diphtheria. Behring’s studies lowered the mortality rate of diphtheria in Germany through serum therapy and vaccination, especially since vaccination confers protection to both mother and infant during pregnancy and after birth.