At the turn of the 20th century, U.S. scientists proposed the control of reproduction to advance society based on the idea that genes determine individuals’ socially relevant traits. In 1910, prominent biologist Charles Davenport defined this project, known as eugenics, as “the science of human improvement by better breeding.” The false claim that scientists can isolate, test for, and quantify inherited characteristics that determine success in an unequal society was essential to eugenicists’ theory that social inequality comes from biology.

Eugenicists’ ideas found fertile ground in America, where they provided a scientific framework to justify the efforts of U.S. elites to preserve the unjust social order they had violently erected in prior centuries. That legacy has spanned decades into the present day.

One of the most widespread and devastating eugenicist weapons has been state-imposed sterilization to rid society of “socially inadequate” members. In March 1924, Virginia lawmakers passed a law that authorized the forced sterilization of people confined to government asylums because they were deemed “feebleminded.” In the 1927 case Buck v. Bell, Justice Oliver Wendell Holmes upheld the law’s constitutionality, infamously declaring that “three generations of imbeciles are enough.”

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In the following years, the number of states with forced sterilization laws grew to 30. Virginia’s Racial Integrity Act, not struck down until 1967, prohibited anyone who wasn’t white from marrying a white person, to discourage perceived contamination of the white race. Influenced by eugenics lobbyists, Congress passed the National Origins Act of 1924, imposing quotas that effectively cut off immigration from Southern and Eastern Europe, regions deemed to have genetically inferior races.

The condemnation of the eugenics-inspired Nazi Holocaust put an end to mainstream support for explicitly eugenicist science, now seen as empirically and ethically flawed. But eugenics’ ideological underpinning — the belief that social inequalities stem from biological differences — has survived.

Dorothy Roberts, a sociologist at the University of Pennsylvania, is among the panelists discussing the history of eugenics in America at the National Constitution Center on May 2.

Claims of innate race and class differences provided scientific backing for a white backlash against the Civil Rights Movement’s gains. In the 1970s, Berkeley psychologist Arthur Jensen argued that black children were innately incapable of greater academic achievement. The 1994 controversial bestseller The Bell Curve: Intelligence and Class Structure in American Life, by Harvard psychologist Richard J. Herrnstein and political scientist Charles Murray, rehashed the claim that race and class disparities stem from differences in inherited cognitive ability, which could not be eliminated through social interventions.

Even today, it would be a mistake to believe this dangerous idea has been relegated to the ranting of white supremacist extremists.

Researchers continue to look for genetic determinants of racial gaps in health, income, education, and incarceration, even though forms of structural racism provide well-established explanations. Just two examples: One 2007 study in the American Journal of Obstetrics and Gynecology tested the hypothesis that the “black race independent of other factors increases the risk of extreme preterm birth.” Despite failing to control for important social and environmental factors and presenting no genetic data, the authors concluded that their findings “suggest a probable genetic component that may underlie [this] public health problem.” In 2017, a Molecular Psychiatry study claimed its findings marked “a turning point” because they make it possible “to predict educational achievement for individuals directly from their DNA.”

Eugenicist science also continued to drive damaging social policies and rhetoric. In the 1960s and 1970s, hundreds of thousands of low-income individuals — disproportionately black, Puerto Rican, Mexican immigrant, and Native American women — were coercively sterilized under federally funded programs. A 1990 Philadelphia Inquirer editorial proposed Norplant, a long-acting chemical contraceptive, as the answer to the staggering rates of black child poverty. Radical changes in welfare law, fueled by negative images of black “Welfare Queens,” denied benefits to mothers receiving public assistance, aimed at deterring them from having more children. President Trump attributes his success to having “the winning gene,” which he inherited from his German ancestors. And assertions of innate white superiority circulate in the media more freely now than in recent decades.

The myth that social inequalities are caused by biological differences blames those marginalized by structural injustices for their own disadvantages — justifying policies that intervene in their bodies rather than calling for social change. At a time when social disparities are widening and government authoritarianism is intensifying, this false idea is as dangerous today as it was in the eugenics era. We can’t think of racial determinism as a relic of the past, or else we run the risk of replicating the injustices it has produced.

Dorothy Roberts is the George A. Weiss University Professor of Law & Sociology at University of Pennsylvania and author of the books Fatal Invention, and Killing the Black Body: Race, Reproduction, and the Meaning of Liberty. She will be among the panelists participating in the History of Eugenics in America program at the National Constitution Center on May 2. Visit constitutioncenter.org/debate for tickets.