Charles Benedict Davenport, Madison Grant, and Henry Fairfield Osborn founded the Galton Society for the Study of the Origin and Evolution of Man, or the Galton Society, in New York City, New York, in 1918. The Galton Society was a scientific society that promoted the study of humans in terms of race in service to the US eugenics movement. The Galton Society was named in honor of Francis Galton who first coined the term eugenics in 1883. Galton and other eugenics proponents claimed that the human species could improve through selective breeding that restricted who could have children. Some of the society members were scientists from a wide range of disciplines who supported the now disproven notion that fundamental biological differences exist between races that may justify the control of human reproduction. The Galton Society drew on the scientific credibility and influence of its members to advocate for eugenics programs, such as immigration restriction laws, in the US.

In 1912, Henry Herbert Goddard published The Kallikak Family: A Study in the Heredity of Feeble-Mindedness, hereafter The Kallikak Family, in which he argues that people inherit feeble-mindedness, which is presently known as intellectual disability. Feeble-mindedness, according to Goddard, is the source of, what he refers to as, degeneracy, including behaviors such as alcoholism, criminal behavior, prostitution, and sexual promiscuity. At the time Goddard wrote his book, many researchers questioned whether people inherited what they considered bad traits, such as feeble-mindedness, criminality, and immorality, and what people could do to get rid of such bad traits. Those ideas reflected the emerging eugenics movement of the early twentieth century. In The Kallikak Family, Goddard explores ideas central to eugenics, including how people can increase good traits and reduce bad traits in the population, For decades, supporters of eugenics cited The Kallikak Family as proof that people inherit such traits, but more recent investigations have discredited Goddard's research as bad science, poorly conceived and biased.

Vasovasostomy is a microsurgical procedure to restore fertility after vasectomy, a surgery that sterilizes the patient by severing the vas deferentia, the tubes that carry the sperm from the testes to the penis. After a vasectomy, a patient may have various reasons for wanting to reverse the procedure, such as new opportunities for having children or a new romantic partnership. A vasovasostomy involves reestablishing the flow of sperm through the vas deferens by reconnecting the severed ends of the tube. In 1919, in the United States, William C. Quinby performed the first recorded successful vasovasostomy. Modern improvements on the surgery have led to its adoption as a microsurgery, a procedure that involves a microscope and specialized microscopic instruments. Surgical research over the twentieth century into reconnecting a blocked vas deferens and the resulting microsurgical technique for vasovasostomy has provided a way for people to regain their fertility after a vasectomy.

No-scalpel vasectomy, or NSV or keyhole vasectomy, is a surgical method of sterilization that involves puncturing the skin of the scrotum to access the vas deferens, a tube that carries spermatozoa, or sperm, from the testes to the penis. The surgeon performing the procedure blocks the flow of sperm through the vas deferens, sterilizing the patient. NSV is a less invasive procedure, as it does not use a scalpel to make a deep cut on sensitive scrotal tissue. Typically, urologists perform NSV with the purpose of rendering the patient sterile while not altering other functions of the testes, scrotum, and penis. Li Shunqiang developed the technique in China in 1974 as a less invasive method of vasectomy for male patients. Li’s development of NSV provided an alternative method to vasectomies that rely on making incisions into the scrotum with a blade. NSV gained wide use as a sterilization technique, providing a path for males to take greater responsibility for contraception and family planning.

Harry Clay Sharp was a surgeon who performed one of the first recorded vasectomies with the purpose of sterilizing a patient. Sterilization is the practice that makes a person unable to reproduce, and vasectomy accomplishes that by severing the vasa deferentia, the sperm-carrying tubes in the male reproductive system. Historically, sterilization procedures have varied in techniques, goals, and risks, but Sharp’s method of vasectomy allowed restriction of a patient’s reproductive functions without significantly affecting other bodily functions. Historians have associated Sharp’s use of the procedure, primarily on prison inmates, with eugenics, a movement with the goal of bettering humans via selective reproductive practices. With vasectomy, Sharp was able to sterilize people whom he did not deem fit to reproduce. Beyond simply pushing forward a new surgical method of sterilization, Sharp’s political advocacy led to the use of his technique as a method of eugenicist control over human reproduction, especially in Indiana.

On March 28, 1978, in Stump v. Sparkman, hereafter Stump, the United States Supreme Court held, in a five-to-three decision, that judges have absolute immunity from lawsuits involving any harm their judicial decisions cause. Linda Sparkman, who was unknowingly sterilized when she was fifteen years old in 1971, sued Harold Stump, the county circuit court judge who signed the petition to allow Sparkman’s mother to have her sterilized. Sparkman’s mother stated to Stump that she wanted her daughter sterilized because of Sparkman’s alleged mental deficiencies and sexual promiscuity. Sparkman argued that Stump violated her Fourteenth Amendment rights to due process because nobody informed her about the nature of the procedure and because Stump did not perform typical court proceedings. Stump argued that, because he was acting within his role as a judge, the doctrine of judicial immunity prevented his liability from lawsuit. Stump strengthened the impunity with which judges can act, including acts found to be unconstitutional, regardless of any rights upon which such actions may infringe.

Eugen Steinach researched sex hormones and their effects on mammals in the late nineteenth and early twentieth centuries in Europe. He experimented on rats by removing their testicles and implanting them elsewhere in their bodies, and he found that the testes interstitial cells produce male sex hormones. He developed the Steinach Rejuvenation Procedure, which he claimed could rejuvenate men by increasing their production of sex hormones. Steinach’s work on female sex hormones and on ovarian extracts led to the development of the first standardized injectable estrogen. Steinach’s research on reproductive hormones helped researchers explain the roles of sex hormones and develop hormone drugs.