A world history of eugenics: Biology is not destiny
Anyone who studies or teaches world history knows that it’s messy and complex; however, some lessons stand out clearly because of the mass of evidence behind them. Here’s an example: Biology does not determine destiny.
Across time and place, societies have tried to predict the future of individuals and nations by ranking human beings according to race, gender, ability, or ancestry. Early historians sometimes accepted these categories as explanations for why societies rose or fell. Yet decades of scholarship demonstrates that while biology inevitably influences the life experiences of humans, it does not determine their moral worth, civic belonging, or social value.
The belief that a person’s biology defines their destiny is the core idea of eugenics, a bundle of theories and practices that rests on the idea that human traits are inherited and that governments should have the authority to judge which members of society are biologically “fit” or “unfit.” In practice, eugenics has led to policies like forced sterilization, marriage restrictions, segregation, and immigration limits. It has also been used to support genocidal policies—including the Nazi extermination of people with disabilities, Jews, Romany people, and others they deemed “subhuman” during the 1930s and 1940s.
Eugenics was not the first set of beliefs by which people were “othered.” Witness, for example, the utterly ridiculous nineteenth-century practice of phrenology—measuring a person’s skull to predict their mental abilities and character. But eugenics took things a step further by applying biological determinism to whole societies, making it the ideology behind the Holocaust, Jim Crow, the Asian Exclusion Act, apartheid, and other twentieth-century atrocities. Some of the ideas behind eugenics remain stubbornly persistent, even in our world today. Studying the global history of eugenics and the damage it has caused gives teachers an opportunity to help students think critically about science, power, and the ways societies—including our own—decide whose lives are valued, and whose are not.
The rise of global eugenics, 1912–1948
At the beginning of the twentieth century, eugenics was widely regarded in many intellectual and political circles as a modern, scientific solution to social problems. Prominent intellectuals like Harry Laughlin and Charles Davenport promoted eugenics thinking, and leaders like Theodore Roosevelt and California Governor Hiram Johnson tried to put it into practice. The topic garnered enough interest for International Eugenics Congresses in 1912, 1921, and 1932. These gatherings were not marginal events. They were global forums where ideas about heredity, reproduction, and migration were exchanged, refined, and exported. They helped transform eugenics from a minor academic theory into an international toolkit for managing populations. Within a few decades, countries across the world had translated these ideas into policies that gave rise to sterilization campaigns, institutionalization, immigration quotas, and population regulation.
The first congress, held in London in 1912, reflected early enthusiasm for eugenics as a scientific answer to societal issues. Delegates from Europe, North America, and various colonies debated how to improve the “quality” of populations, often by identifying and excluding those labeled “defective.” Immigration quickly became central. Mass migration was framed as a biological threat to national health, and border controls were presented as protective measures.
At the second congress, hosted in 1921 by the American Museum of Natural History in New York City, the United States positioned itself as a model. Attendees praised IQ testing at Ellis Island and in juvenile institutions, especially in California. By this time, eugenics could be found in seemingly everyday practices, such as “Beautiful Baby” contests that judged the “fitness” of babies based on a white upper-class ideal, or making women walk through cutouts to show that they had “perfect” proportions.
The debate around eugenics in America in this period was particularly concerned with measuring the desirability of different immigrant populations. These discussions influenced the passage of the Johnson-Reed Act of 1924. Harry Laughlin, a prominent eugenicist, testified before Congress and helped shape the intellectual justification for new immigration restrictions. At the committee hearing, he claimed, “we want to prevent any deterioration of the American people due to the immigration of inferior human stock.” To help enforce the new immigration laws, Congress established the US Border Patrol later in 1924. The climate of scientific legitimacy surrounding eugenics meetings reinforced support for the Supreme Court’s 1927 Buck v. Bell decision, which upheld states’ practices of compulsory sterilization for the “unfit,” including people with intellectual disabilities.
These policies influenced other nations, including Germany, where Adolf Hitler wrote admiringly of US racial legislation. They also resonated in Canada and Australia, where immigration policy increasingly favored white European settlers. In Latin America, countries such as Brazil and Mexico blended eugenic ideas with public health campaigns focused on hygiene, motherhood, and national “improvement.”
By the third eugenics congress in 1932, held again in New York City, organizers celebrated what they called “A Decade of Progress in Eugenics.” The movement appeared to be at its height. Just months later, the Nazi Party came to power in Germany, paving the way for the Holocaust, with its racial laws and forced sterilization, which was essentially genocide carried out in the name of biological purification.
The Holocaust revealed the most extreme consequences of eugenic ideology. Yet eugenic reasoning did not end with Nazi Germany. Even after the Second World War, sterilization programs continued in Japan and Sweden. Apartheid policies in South Africa drew on related assumptions about racial hierarchy. Public exposure at the Nuremberg and Doctors’ Trials discredited the language of eugenics, but many of its underlying assumptions proved more durable.
Eugenics violence undercover, 1948–today
After these public trials, the term eugenics became politically toxic. But many of its practices survived under new names and institutional frameworks, sometimes promoted as “family planning.” In India, population control programs culminated in mass sterilizations in the 1970s. In Peru, forced sterilization campaigns in the 1990s disproportionately targeted Indigenous women. In Australia and across the Pacific, Indigenous communities continued to experience reproductive control through welfare and child-removal policies. The consequences of these policies—social, political, and personal—remain visible today.
Modern genetic science presents both promise and responsibility. Technologies such as CRISPR and advances in genomics can alleviate suffering and prevent disease. However, when genetic enhancement is framed in terms of producing “stronger” or “fitter” populations, or when access is shaped by inequality and coercion, older assumptions about whose lives are more valuable can quietly reemerge. For educators, this history provides essential context for classroom discussions about science, ethics, and power.
Eugenic practices have followed recognizable patterns throughout history: Certain people are imprisoned and segregated—they’re removed from public life. They are stripped of their rights, neglected, and exploited. In many cases, they are subjected to forced medical procedures and are the target of dehumanizing laws. These practices don’t always carry the label eugenics. Yet historically, they have drawn on similar assumptions: Some lives are inherently more valuable, productive, or worthy than others.
Around the world today, ideas that echo eugenic thinking continue to circulate. They find new audiences and result in new policies around immigration, birth rates, genetic enhancement, disability, and criminal profiling. Helping students recognize these historical patterns does not mean collapsing all contemporary policy debates into eugenics. It means equipping them with the historical perspective to ask sharper questions about how biological claims are used in public life.
A global movement against eugenics
But that’s just half the story. The other half is about the global nature of resistance to eugenics.
Just as eugenics developed through global networks, the reach of those who have opposed it has also been global. Activists, scholars, educators, artists, and survivors have built transnational coalitions to document harm, seek reparations, and prevent the resurgence of biological hierarchies.
Historians play an important role in this work, helping governments and institutions confront histories long denied or buried. In Japan, researchers supported campaigns that collected and amplified the testimonies of survivors of the 1948 Eugenic Protection Law, contributing to a national apology and reparations. In California, collaborations among scholars, social justice organizations, educators, artists, and journalists exposed both early twentieth-century sterilization programs and more recent abuses in prisons. In 2021, these efforts helped secure reparations and educational initiatives.
Since 2020, growing awareness of eugenic legacies has led to truth‑telling actions, often led by Indigenous communities. In Vermont, an ongoing truth and reconciliation commission led to an apology by the state for its role in eugenics. In Australia, Aboriginal and Torres Strait Islander activists, working with researchers and artists, have advanced truth‑telling initiatives. In Aotearoa New Zealand, Māori scholars, activists, and educators have traced how eugenics shaped colonial governance. Similar truth-telling and justice efforts are underway in Korea, Brazil, and Scandinavia.
Through initiatives like From Small Beginnings, organizers are working to imagine what a more just, inclusive, and equitable future looks like, and to determine the steps needed to achieve this. In January 2026, representatives of this expanding global anti-eugenics community met in Mexico City under the murals of Colegio San Ildefonso to debate future interventions, including the possible establishment of the first-of-its-kind Global Anti-Eugenics Centre. While a century ago, eugenics advocates worked deliberately to internationalize their ideas and influence policy across borders, today, educators, researchers, and community leaders are building international networks of their own, not to rank human worth, but to defend it.
For teachers, this history offers more than a warning. It offers a framework for classroom inquiry. How does scientific authority shape public policy? How do ideas travel globally and become law? How do societies draw—and redraw—the boundaries of belonging? What kinds of future do we want? Teachers might also want to link discussions of eugenics to the study of the Holocaust, apartheid in South Africa, or the struggle for civil rights and global liberation. But remember: Eugenics is not just history. The questions it raises about who counts, who decides, and whose lives are valued continue to surface in debates about genetics, reproduction, public health, immigration, response to climate change, and social policy. Teaching this history equips students to approach those debates with historical perspective and ethical clarity.
About the authors: Trevor Getz is Professor of African History at San Francisco State University. He has written eleven books on African and world history, including Abina and the Important Men. He is also the author of A Primer for Teaching African History, which explores questions about how we should teach the history of Africa in high school and university classes.
Benedict Ipgrave is codirector of the Anti-Eugenics Project and project coordinator of the International Disability Research Program at University College London.
Miroslava Chávez-Garcíais a professor of history at the University of California, Santa Barbara, and holds affiliations in the departments of Chicana/o Studies and Feminist Studies as well as Iberian and Latin American Studies.