Forced sterilization programs, selective breeding incentives, restrictive immigration laws, and the Nazi “euthanasia” campaign are all examples of eugenics. The term covers any attempt to manipulate who reproduces (or who doesn’t) in order to shape the genetic makeup of a population. Some examples involved outright government coercion; others operated through social pressure, legal restrictions, or economic incentives. Understanding the range of real-world cases makes the concept far clearer than any textbook definition.
What Eugenics Actually Means
Francis Galton coined the term in the late 1800s, defining it as the study of factors “under social control that may improve or impair the racial qualities of future generations either physically or mentally.” In practice, eugenics became a movement to encourage reproduction among people considered “fit” and prevent it among those labeled “unfit.” That labeling was deeply influenced by racism, classism, and ableism, and the science behind it was flawed from the start. The National Human Genome Research Institute now describes eugenics as a “scientifically erroneous and immoral theory.”
Eugenics is typically split into two categories. “Positive” eugenics encourages people deemed genetically desirable to have more children, through financial rewards, propaganda, or social pressure. “Negative” eugenics aims to stop people deemed undesirable from reproducing, through sterilization, institutionalization, marriage restrictions, or killing. Both types appeared widely in the 20th century, and some forms persist today.
Forced Sterilization in the United States
The most straightforward example of eugenics in American history is the wave of compulsory sterilization laws that began in 1907, when Indiana became the first state to authorize the procedure. Over the following decades, similar laws spread across the country. By World War II, roughly 60,000 people in the United States had been sterilized against their will. Targets were disproportionately poor, disabled, Black, Latino, Indigenous, or institutionalized.
The legal foundation for these programs was cemented in 1927 when the Supreme Court ruled 8 to 1 in Buck v. Bell. The case involved Carrie Buck, a young Virginia woman wrongly labeled “feebleminded.” Justice Oliver Wendell Holmes Jr. wrote the majority opinion, declaring: “Three generations of imbeciles are enough.” Holmes went further, arguing that the nation must sterilize those who “sap the strength of the State” to “prevent our being swamped with incompetence.” The ruling gave states explicit constitutional cover to sterilize citizens they considered unfit, and it has never been formally overturned.
The Immigration Act of 1924
Eugenics didn’t only target individuals already living in the United States. It also shaped who was allowed to enter the country. Harry Laughlin, a prominent eugenicist, was appointed “Expert Eugenics Agent” to the House Committee on Immigration and Naturalization in the early 1920s. Under his guidance, Congress passed the Johnson-Reed Immigration Restriction Act of 1924.
The law capped immigration quotas at 2% of each nationality’s existing U.S. population, a formula designed to drastically reduce arrivals from eastern and southern Europe, including Russia, Poland, Italy, and the Balkans. Laughlin argued that people from these regions included an “excessively large proportion” of the “unfit” and “insane.” The act also all but shut down immigration from East Asia and the Indian subcontinent. This was eugenics applied not through surgery but through border policy, filtering entire populations based on pseudoscientific claims about genetic worth.
Nazi Germany’s “Euthanasia” Program
The most extreme example of eugenics in history is the Nazi regime’s systematic murder of disabled people. Germany’s leaders drew direct inspiration from American sterilization laws before escalating far beyond them. The T4 program, launched in 1939, targeted people with schizophrenia, epilepsy, dementia, encephalitis, and other chronic psychiatric or neurological conditions. It also targeted people who had been institutionalized for more than five years or who were “not of German or related blood.”
At least 10,000 disabled children were killed through the program during the war years. Between January 1940 and August 1941 alone, the regime’s own internal records show 70,273 institutionalized people were gassed at six dedicated facilities. Historians estimate the total death toll reached approximately 250,000 men, women, and children. The T4 program served as a rehearsal for the broader Holocaust, with many of the same personnel and techniques later deployed in the death camps.
Unauthorized Sterilizations in California Prisons
Eugenics is not only a historical phenomenon. A 2013 investigation by the Center for Investigative Reporting found that close to 150 unauthorized sterilizations were performed on women in California prisons between 2006 and 2010. A subsequent audit by the California state auditor confirmed that 144 women were sterilized without proper adherence to required consent protocols. The physician who performed many of the procedures expressed prejudices about which women should be allowed to reproduce.
State Senator Hannah-Beth Jackson connected the prison sterilizations directly to California’s eugenic past, stating that “pressuring a vulnerable population, including at least one instance of a patient under sedation, to undergo these extreme procedures erodes the ban on eugenics.” The case demonstrated that coercive reproductive control can continue even in an era when eugenics is officially condemned.
Genetic Screening and the “New Eugenics” Debate
Modern reproductive technology raises a subtler question. Preimplantation genetic diagnosis (PGD) allows parents undergoing IVF to screen embryos for genetic conditions before implantation. The stated goal is to help families avoid serious heritable diseases. But some bioethicists argue that PGD functions as a form of eugenics because its practical effect is reducing the number of people born with certain genetic conditions.
Because PGD works with multiple embryos and doesn’t involve abortion, it is significantly more effective as a selection tool than older forms of prenatal testing. Critics warn it could expand into selection based on non-medical traits like height, intelligence, or appearance, creating what one analysis in a major bioethics journal called “a full-blown free-market eugenics.” Unlike 20th-century programs, this version wouldn’t require government coercion. Instead, it would be driven by consumer choice, social pressure, and market forces.
Germline gene editing using CRISPR technology pushes the question even further. As of recent counts, about 40 countries discourage or ban germline editing for reproductive purposes, including 15 nations in Western Europe. Researchers and bioethicists broadly agree that editing the DNA of future generations should not be attempted for reproduction until safety is established. The concern isn’t just technical risk. It’s that even therapeutic gene editing could put society on a path toward selecting for enhancement traits, reviving eugenic thinking in a high-tech form.
How These Examples Connect
What links a 1907 Indiana sterilization law, a 1924 immigration quota, a Nazi gas chamber, a California prison procedure room, and an IVF laboratory is the same underlying logic: some people’s genes are worth passing on and others’ are not. The methods range from violent to voluntary, from government-mandated to consumer-driven. But the core assumption, that society benefits from controlling who reproduces, is the defining feature of eugenics in every form it takes.
The critical difference between genetic medicine and eugenics lies in coercion, intent, and who holds the power. Modern genetic counseling operates on a principle of nondirective guidance, meaning counselors present information and let families make their own decisions. Historical eugenics did the opposite: the state decided who was fit, and individuals had no say. The line between the two can blur, which is exactly why the history matters.