Sam Trejo Headshot

Assistant Professor of Sociology


Charles H. Mcllwain University Preceptor


PRINCETON UNIVERSITY


 Contact

samtrejo [at] princeton [dot] edu


(609) 258-4436


187 Wallace Hall
Princeton, NJ 08544


 Links

Curriculum Vitae

Google Scholar

Princeton Sociology Department

Princeton Biosociology Lab

What We Inherit


 Popular Writing

Los Angeles Times

Scientific American


 Fun

Judge John Hodgman I

Judge John Hodgman II

Biography


My name is Sam Trejo—I am a sociologist and demographer interested in how social and biological factors jointly shape human development across the life-course. I specialize in quasi-experimental, computational, and biosocial quantitative methods. My research has been published in a range of academic journals, including PNAS, Science Advances, the American Journal of Sociology, and Sociological Science. I also co-lead the Princeton Biosociology Lab.

My work encompasses two primary research areas. The first integrates genomic information into the social and behavioral sciences. This includes utilizing polygenic scores to analyze genetic risk factors and gene-environment interactions, as well as employing genetic ancestry measures to explore racial and ethnic identity formation and demographic change. My second research area leverages field and natural experiments to investigate the factors that produce educational and health inequalities, with particular attention to the reciprocal relationship between education and health. This work has examined topics such as childhood lead exposure, fatal school shootings, and economic segregation.

I recently co-authored a book with Stanford University bioethicist Daphne Martschenko entitled What We Inherit: How New Technologies and Old Myths Are Shaping Our Genomic Future (forthcoming from Princeton University Press). Over the past decades, human genetics has rapidly produced an array of unprecedented genomic tools. In the book, Daphne and I debate and discuss the social, ethical, and policy issues raised by this DNA revolution. While we disagree on many points, we share a firm belief that successfully navigating the transition to a society with increasingly accurate and available genetic prediction requires taking seriously both the impact of DNA and the dangers of pernicious genetic myths. What We Inherit will be released on February 3, 2026.

When not puzzling over human behavior, I enjoy biking, playing board games, and spending time with my wife Marissa and our dog Pickle. The R code used to create this website is available here.


Research

  * Joint lead authorship   § Senior authorship ● PDF   ● FAQ   ● Data/Code   ● Pre-Reg

● Working Papers


DNA Reveals the Growing Ancestral Diversity of the United States

Sam Trejo and Marissa Thompson. APC Working Paper.


DNA, Self-Reported Ancestry, and Social Scientific Inquiry

Luyin Zhang and Sam Trejo§. SocArXiv.


Does Standard Adjustment for Genomic Population Structure Capture Direct Genetic Effects?

Ramina Sotoudeh*, Sam Trejo, Arbel Harpak, and Dalton Conley§. bioRxiv.


○ Published & Forthcoming Papers


2026


Policing the Boundaries of Blackness: How Black and White Americans Evaluate Racial Self-identifications

Marissa Thompson, Sam Trejo, AJ Alvero, and Daphne Martschenko. Forthcoming at American Journal of Sociology. ●


2025


Genotypic and Socioeconomic Risks for Depressive Symptoms in Two U.S. Cohorts Spanning Early to Older Adulthood

David A. Sbarra, Sam Trejo, K. Paige Harden, Jeffrey C. Oliver, and Yann C. Klimentidis. Journal of Psychopathology and Clinical Science.


2023


Beware the Phony Horserace between Genes and Environments

Sam Trejo* and Daphne Martschenko*. Behavioral and Brain Sciences. ●


2022


Ubiquitous Bias and False Discovery Due to Model Misspecification in Analysis of Statistical Interactions: The Role of the Outcome’s Distribution and Metric Properties

Benjamin W. Domingue, Klint Kanopka, Sam Trejo, Mijke Rhemtulla, and Elliot M. Tucker-Drob. Psychological Methods. ● ●


Ethical, Anticipatory Genomics Research on Human Behavior Means Celebrating Disagreement

Daphne Martschenko* and Sam Trejo*. Human Genetics and Genomics Advances.


2021


Modeling Interaction and Dispersion Effects in the Analysis of Gene-Environment Interaction

Benjamin W. Domingue*, Klint Kanopka, Travis T. Mallard, Sam Trejo, and Elliot M. Tucker-Drob§. Behavior Genetics. ● ●


FoGS Provides a Public FAQ Repository for Social and Behavioral Genomic Discoveries

Daphne Martschenko, Benjamin W. Domingue, Lucas J. Matthews, and Sam Trejo. Nature Genetics. ● ●


2020


Interactions Between Polygenic Scores and Environments: Methodological and Conceptual Challenges

Benjamin W. Domingue, Sam Trejo, Emma Armstrong-Carter, and Elliot Tucker-Drob. Sociological Science. ●


Local Exposure to School Shootings and Youth Antidepressant Use

Maya Rossin-Slater*, Molly Schnell*, Hannes Schwandt*, Sam Trejo, and Lindsey Uniat. Proceedings of the National Academy of Sciences. ●

PRESIDENTIAL ECONOMIC REPORT, WASHINGTON POST, LOS ANGELES TIMES, THE HILL


The Earliest Origins of Genetic Nurture: The Prenatal Environment Mediates the Association Between Maternal Genetics and Child Development

Emma Armstrong-Carter*, Sam Trejo*, Liam Hill, Kirsty Crossley, Dan Mason, and Benjamin W. Domingue§. Psychological Science. ● ●


2019


Genetics and Education: Recent Developments in the Context of an Ugly History and an Uncertain Future

Daphne Martschenko*, Sam Trejo*, and Benjamin W. Domingue*. AERA Open.


2018


Schools as Moderators of Genetic Associations with Life Course Attainments: Evidence from the WLS and Add Heath

Sam Trejo*, Daniel W. Belsky, Jason D. Boardman, Jeremy Freese, Kathleen Mullan Harris, Pamela Herd, Kamil Sicinski, and Benjamin W. Domingue§. Sociological Science.


● Resting Papers