Political leaders like United States President Donald Trump and business oligarchs like Elon Musk have increasingly suggested that human behaviour and social outcomes are rooted in genetics.
Trump has repeatedly suggested that problematic behaviours are genetic and inherent, while Musk has advocated for “intelligent” people to have children. His Grokipedia even frames racist concepts like racial nationalism positively while drawing on eugenic ideas, claiming that preserving distinct racial genetic profiles “maximizes individuals’ inclusive fitness.”
These arguments are taking us back to one of the darkest periods in human intellectual history: when eugenics was alive and well. Eugenics is the mistaken belief that a society’s genetic pool can be “improved” by limiting the reproduction of those deemed inferior and encouraging the breeding of those deemed superior.
Eugenics is now regarded as “the most egregious example of the destructive misuse of science in all human history,” as evolutionary biologist Richard Prum put it.
Yet this pseudoscientific way of thinking has not disappeared. It has re-emerged in new forms, primarily among tech capitalists and conservative politicians advocating for policies like forced migration, fertility assistance and genetic engineering to create a “fitter” nation.
Read more:
Racism never went away – it simply changed shape
In our recent book, The American Gene: Unnatural Selection Along Class, Race, and Gender Lines, we show that differences in complex behavioural traits among groups are not the natural outcome of inborn human biology, but the product of systemic economic inequality.
We can illustrate this by focusing on two of the most popularly discussed in the nature-versus-nurture debate: health and intelligence.
The limits of the human genome
The US$3 billion Human Genome Project set out to identify “the key genes underlying the great medical scourges of humankind.” Bill Clinton called it “the most important, most wondrous map ever produced” when he was U.S. president.
Yet except for rare diseases caused by one or a few genes, genomic data has had limited success in predicting complex diseases like heart disease, cancer, mental health disorders or addiction.
(AP Photo/Paul Franz)
Scientists have found dozens of genetic variations associated with complex diseases, but the combined effects of these genes have explained very little about heritable risk. Even with the complete human genome sequenced, predicting health outcomes from genetics has proven challenging.
In fact, in 2013, the Food and Drug Administration ordered 23andMe to stop marketing certain genetic disease risk information to consumers until they received regulatory clearance.
Environment shapes health more than genes
Some scientists, including molecular biologist James Watson, the first director of the Human Genome Project and a disgraced Nobel laureate, have argued that genetics largely determine health hierarchies.
He once suggested that New Jersey’s high cancer rates were mostly due to residents’ “genetic constitution” rather than environmental factors.
This logic is flawed. It would suggest that the people of New Jersey had uniquely cancer-prone DNA compared to the rest of the population, which seems unlikely. Further undermining Watson’s theory is the fact that cancer rates followed the changing location of the chemical industry, which fled New Jersey’s increasingly costly environmental regulations for Louisiana.
“Cancer Alley” in Baton Rouge, Louisiana — an 85-mile stretch of the Mississippi River lined with some 200 fossil fuel and petrochemical production plants — became home to the nation’s highest cancer rates, affecting the region’s disproportionate Black and Brown population.
In the words of bio-statistician Melanie Goodman: “ZIP Code is a better predictor of health than genetic code.”
Further evidence against genetic determinism comes from migrant studies. Research has found ethnic groups with low breast cancer rates in their home countries, such as China, Japan and the Philippines, often experience higher disease rates after migration.
Similar patterns appear in studies of coronary heart disease among people of Japanese ancestry who lived in Japan, Hawaii and California. Those who adopted more westernized lifestyles had higher rates of disease.
Intelligence is a product of opportunity
Researchers like Richard Hernstein, Charles Murray, David Reich and Nicholas Wade have insisted on a link between genetics, race or ethnicity, and what they describe as a hierarchy of intelligence.
In these arguments, Ashkenazi Jews are often placed at the top of the hierarchy, while people of African descent are placed lower. Although the discussion always revolves around genetic inheritance, they have yet to identify the specific genes that would justify this hierarchy.
Where proponents attempted to provide empirical support, the argument often rested on a residual claim: even after accounting for all the social variables that might influence intelligence, an unexplained component remained and was therefore presumed to be genetic.
On the other side of the debate are researchers like James Flynn, who argued intelligence is determined more by environment than genetics.
Flynn documented a steady rise in intelligence test scores across the 20th century in a pattern now known as the “Flynn Effect.” He found that between 1933 and 1983, American IQs increased by around three points per decade. He argued people’s minds were sharpened by better education and more intellectually demanding jobs and hobbies.
Flynn also found larger impacts in lower-income nations. Kenya and several Caribbean nations, for example, had much larger increases in IQ scores than Scandinavian countries because, he argued, the conditions for learning had improved more in the former nations than the latter.
Lived experience influences our genes
Advances in the revolutionary field of epigenetics have shifted the nature-versus-nurture debate by identifying a pathway through which lived experience can impact what were previously thought to be fixed processes.
Epigenetics refers to mechanisms that affect gene expression — how much a gene is used or not — without changing the DNA sequence itself. These mechanisms function somewhat like a dimmer switch, turning genes on and off, or adjusting the intensity of their effects.
Growing evidence suggests that epigenetic mechanisms are impacted by the conditions in which people live, which in turn influence human traits and outcomes. Some of these epigenetic changes may even be transmitted across generations.
In other words, nurture has a direct influence on nature.
Claims about the supposed genetic superiority of some human beings over others rarely account for the complexity of these additional types of inheritance.
Opportunity matters more than genetics
A growing body of research suggests that social and economic opportunity plays a far greater role in shaping human outcomes than genetic inheritance.
As biologist Siddhartha Mukherjee pointed out, “it is impossible to ascertain any human, genetic potential without first equalizing environments.”
Decades earlier, Henry Wallace, who served as vice-president under Franklin D. Roosevelt, similarly suggested that if children from rich and poor families were given the same food clothing, education, care and protection, class lines would likely disappear.
Historical evidence supports this view. Our research shows that when structural barriers are reduced and marginalized groups have the same opportunities as more privileged groups, inequalities shrink dramatically.
By way of example, the economic and social changes following U.S. civil rights legislation led to major improvements in the health, education and income of Black Americans — despite no change in their genetic makeup — highlighting the role of structural racism and social policy.
People should be significantly more concerned with the effects of the policies imposed by the Trumps and Musks of the world than the DNA passed on by their parents.
