The American Eugenics Society (AES) was established in the US by Madison Grant, Harry H. Laughlin, Henry Crampton, Irving Fisher, and Henry F. Osborn in 1926 to promote eugenics education programs for the US public. The AES described eugenics as the study of improving the genetic composition of humans through controlled reproduction of different races and classes of people. The AES aided smaller eugenic efforts such as the Galton Society in New York, New York, and the Race Betterment Foundation in Battle Creek, Michigan, and it influenced eugenic policy set by the US Supreme Court in cases including Buck v. Bell (1927) and Skinner v. Oklahoma (1942). The AES was renamed the Society for the Study of Social Biology in 1972.

Harry Hamilton Laughlin helped lead the eugenics movement in the United States during the early twentieth century. The US eugenics movement of the early twentieth century sought to reform the genetic composition of the United States population through sterilization and other restrictive reproductive measures. Laughlin worked as superintendent and assistant director of the Eugenics Research Office (ERO) at Cold Spring Harbor Laboratory in Cold Spring Harbor, New York, alongside director Charles Davenport. During Laughlin's career at the ERO, Laughlin studied human familial ancestry, called pedigrees, and in 1922 published the book Eugenical Sterilization in the United States, which influenced sterilization laws in multiple states. Laughlin's support of compulsory sterilization to control the reproductive capacity of entire populations influenced the history of eugenics and reproductive medicine.

Henry Herbert Goddard was a psychologist who conducted research on intelligence and mental deficiency at the Vineland Training School for Feeble-Minded Boys and Girls in Vineland, New Jersey during the early twentieth century. In 1908, Goddard brought French psychologist Alfred Binet and physician Theodore Simon’s intelligence test to the US and used it to investigate intellectual disability in children at the Vineland Training School for Feeble-Minded Boys and Girls. Goddard also wrote a book in 1912 called The Kallikaks: A Study in the Heredity of Feeble-Mindedness, claiming that traits like mental deficiency were heritable traits. His observations and research led Goddard to advocate for sterilization and segregation of the intellectually disabled, which were ideas that reflected the emerging eugenics movement in the US, during the early nineteenth century. Although by the end of his life, psychologists largely dismissed Goddard’s work, schools and the US military used Goddard’s version of Binet and Simon’s intelligence test to identify mental deficiency.

The International Eugenics Congresses consisted of three scientific meetings held in London, England, in 1912 and at the American Museum of Natural History in New York City, New York, in 1921 and 1932. Leonard Darwin, son of Charles Darwin, Henry Fairfield Osborn, the President of the American Museum of Natural History, and Charles Benedict Davenport, founder of the Eugenics Record Office at Cold Spring Harbor Laboratory in New York City presided over the Congresses. Scientists presented research in genetics and shared ideas for putting eugenics into practice, such as preventing people they considered inferior from reproducing through forced sterilization. The three International Eugenics Congresses increased scientific and public support of the eugenics movement in the early twentieth century, and established organizations to pursue eugenics agendas that contributed to the forced sterilization of hundreds of thousands of people in the US and Nazi Germany.

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.

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.

Better babies contests were competitions held in state fairs throughout the US during the early twentieth century in which babies between the ages of 6 and 48 months were judged for their health. In 1908, social activist Mary de Garmo established and held the first better babies contest at the Louisiana State Fair in Shreveport, Louisiana. The contests, mirroring theories established in the US’s eugenics movement of the twentieth century, aimed to establish standards for judging infant health. Nurses and physicians judged infants participating in the contest on mental health, physical health, and physical appearance. In 1913, the Woman’s Home Companion (WHC) magazine cosponsored de Garmo’s better babies contests and introduced the competition to state fairs throughout the US. Better babies contests helped promote routine health assessments of children by medical professionals.

In 1927, the US Supreme Court case Buck v. Bell set the legal precedent that states may sterilize inmates of public institutions because the court argued that imbecility, epilepsy, and feeblemindedness are hereditary, and that the inmates should be prevented from passing these defects to the next generation. On 2 May 1927, in an eight to one decision, the US Supreme Court ordered that Carrie Buck, feebleminded daughter of a feebleminded mother and herself the mother of a feebleminded child, be sterilized under the 1924 Virginia Eugenical Sterilization Act. Buck v. Bell determined that compulsory sterilization laws did not violate due process awarded by the 14th Amendment to the US Constitution. It also bolstered the American eugenics movement and established legal authority for sterilizing more than 60,000 US citizens in over thirty states, until most of the practices ended in the 1970s.

In 1933, an act of the North Carolina legislature created the Eugenics Board of North Carolina, or EBNC, to oversee the practice of sterilization, which is the removal of an individual’s ability to reproduce, in the state. Beginning in the late nineteenth and early twentieth centuries, the US eugenics movement involved both state and non-governmental entities attempting to improve human populations through selective breeding, which included sterilization of those labeled as genetically inferior. In North Carolina, the EBNC headed the state government’s eugenics program and oversaw decisions related to the sterilization of poor and disabled people. By the time of the dissolution of the EBNC in the late 1970s, an estimated 7,600 people had undergone forced sterilization under the board’s approval. Some of them later received funds in the 2010s from the state government in one of the first programs to provide compensation to involuntarily sterilized individuals. The EBNC presided over the sterilizations of thousands of people in North Carolina, prompting one of the first attempts at eugenics reparations in the US.

Paul Bowman Popenoe was a researcher, writer, and social advocate who studied breeding in the United States during the twentieth century, first in plants and then in humans. Popenoe advocated for eugenic policies in California and beyond in the early twentieth century, and he introduced and promoted marriage counseling as a professional service in the US during the mid-twentieth century. The US eugenics movement, in which Popenoe participated, was a scientific and political project in which eugenicists attempted to improve human populations through selective breeding. Participants of the movement often advocated for the implementation of compulsory sterilization laws for certain “undesirable” populations. Though largely disavowed as of 2026, eugenics persisted well into the twentieth century. Through dozens of publications and a lifetime of public advocacy, Popenoe supported policies that led to the forced sterilization of thousands of people in California and popularized counseling as an intervention into people’s marriages and reproductive choices.