The Social Genome: The New Science of Nature and Nurture

“Conley’s new science of nature and nurture suggests that humanity is on the verge of a brave new world.”

Are we—you and I—the products of nature or nature? Why are we interested in books while millions of people are not? The Social Genome contends that nature and nurture shape each other. The book reflects deep advances in science over recent decades. Its findings help to integrate social and biological sciences. But the book also provides real-world considerations for anyone thinking to give life to another human being. 

Professor Dalton Conley at Princeton University provides a layman’s guide to the ways that genes shape every facet of behavior—from physical, emotional, and intellectual traits to the kinds of people we tend to befriend and espouse. But he avoids the either/or arguments of “hereditarians” who believe in the primacy of genes and “blank-slaters” who believe we are mainly shaped by our environment. Dalton Conley demonstrates that this longstanding debate is fundamentally misguided. The true question is not nature versus nurture, but how the two interact to shape how each of us becomes who we become. His findings should shape debates about racial disparities, meritocracy, reproduction, and free will itself.  

How can nurture—the environment—shape nature? Here is one example. Why do many Black people suffer from high blood pressure? Some are born with a predisposition, but evidence shows that if the society where they live discriminates against Black people, the darker their skin, the stronger their hypertension. The skin tone caused by genes elicits an irrational response from the environment. Other facets of “nurture,” not mentioned by Conley, include the quality of diet, housing, and social tranquility.

The Social Genome emerges from a sociogenomics revolution that upends many notions about human development. Sociogenomics brings together advances in molecular genetics and traditional social and behavioral science. The key tool is the polygenic index, which allows scientists to analyze DNA so as to measure a child’s genetic potential. Today, scientists can estimate a child’s adult height, how far they will go in school, and their weight as an adult―all from a cheek swab, finger prick, or vial of saliva.

Conley and other researchers are using this new science to shed light on the ways in which genes shape our world, influencing how each person both creates and responds to the environment around them. Conley reveals a world where children’s DNA influences the nurture they extract from their parents; the genes of our schoolmates affect our likelihood of smoking as much as our own DNA does; and spouses’ genes influence each other’s moods and behaviors. Looking forward, Conley envisions a future where dating, education, public health, and other institutions may be altered by the sociogenomic revolution.

Conley’s key insight is that our genes seek the nurture they need to express themselves and how, in turn, our environments are made partly from the genes of other people. But The Social Genome also raises critical ethical questions about how humans will navigate a future where they have access to far more genetic information than ever before.

“Should Human Life Be Optimized?” This is the question raised by Anna Louie Sussman in The New York Times in March–April 2025.  Her long, three-part article underscores—celebrates or warns against—the growing availability of genetic testing to determine which embryos will leave the laboratory and become human babies. Sussman relates that the US-based Orchid Health Company screens for diseases with whole genome analysis that aims to detect genetic errors linked to severe diseases during IVF (in vitro fertilization) before pregnancy begins and mitigate risks that could affect a future baby. The company screens embryos’ DNA for hundreds of conditions, such as retinitis pigmentosa, which can be traced to a single genetic variant. But the company also goes further, offering what is known as polygenic screening, which gives parents what is essentially a risk profile on each embryo’s propensity for conditions such as heart disease, for which the genetic component is far more complex. 

Complaints about Orchid’s work were detailed by Jocelyn Kaiser in the ScienceAdviser newsletter dated March 29, 2021. The Orchid company announced on December 5, 2020, that it would begin to offer fertility clinics and their hopeful customers the unprecedented option to sequence the whole genomes of embryos conceived by IVF. “Find the embryo at lowest risk for a disease that runs in your family,” touts the company’s website. The cost: $2500 per embryo at that time. 

Although Orchid and at least two other companies have already been conducting more limited genetic screening of IVF embryos, the new test offers something more: Orchid will look not just for single-gene mutations that cause disorders such as cystic fibrosis, but also more extensively for medleys of common and rare gene variants known to predispose people to neurodevelopmental disorders, severe obesity, and certain psychiatric conditions such as schizophrenia.

That new offering drew swift backlash from genomics researchers who claimed that Orchid inappropriately used their data to generate some of its risk estimates. The Psychiatric Genomics Consortium (PGC), an international group of more than 800 researchers working to decode the genetic and molecular underpinnings of mental health conditions, said Orchid’s new test relied on data it produced over the past decade, and that the company violated restrictions against the data’s use for embryo screening.

PGC objects to such uses because its goal is to improve the lives of people with mental illness—not stop them from being born, said University of North Carolina at Chapel Hill psychiatrist Patrick Sullivan, PGC’s founder and lead principal investigator. PGC’s response marked the first time an academic team publicly took on companies using its data to offer polygenic risk scores.

For more than a decade, IVF clinics have been able to pluck a handful of cells out of lab-made embryos and check whether a baby would inherit a disease-causing gene.Even this more limited screening has generated debate about whether it can truly reassure potential parents an embryo will become a healthy baby—and whether it could lead to a modern-day form of eugenics.

But with recent advances in sequencing, researchers can read more and more of an embryo’s genome from those few cells, which can help create so-called polygenic risk scores for a broad range of chronic diseases. Such scores calculate an individual’s odds of developing common adult-onset conditions that result from a complex interaction between multiple genes as well as environmental factors.

Orchid’s screening method sequences more than 99% of an embryo’s DNA and estimates the risk of conditions including the irregular heart rhythm known as atrial fibrillation, inflammatory bowel diseases, types 1 and 2 diabetes, breast cancer—and some of the psychiatric conditions that PGC studies. Orchid scientists have concluded that their whole genome sequencing methods using a five-cell embryo biopsy are accurate and effective at reading the depth and breadth of the genome.

Conley’s new science of nature and nurture suggests that humanity is on the verge of a brave new world. Scientists in Europe are trying to set limits on what can be done with genetic information. Relative to Europe, the United States is a kind of unregulated wild west, as are some Asian countries.