Biography

My name is Sam Trejo—I am a sociologist and demographer who studies how social and biological factors jointly shape human development across the life course. Broadly, my work argues that the boundary between the biological and the social is porous, and that rigorous social science must treat it as such. 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 Demography. I co-lead the Princeton Biosociology Lab.

My work spans two main areas. The first integrates genomic data into the social and behavioral sciences—for instance, using polygenic scores to analyze genetic risk and gene-environment interplay, and leveraging genetic ancestry measures to study racial and ethnic identity formation and demographic change. The second uses field and natural experiments to understand inequality in health and social outcomes, including studies on 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 (Princeton University Press). In recent decades, human genetics has produced an array of unprecedented genomic tools; in the book, Daphne and I debate 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 has been reviewed in the Times Literary Supplement, Undark, Ars Technica, Health Affairs, and Publishers Weekly. Daphne and I discuss the book in a Live Science Q&A and on the Bioethics in the Margins podcast, and I was recently quoted in the New York Times on the book’s policy recommendations regarding genetic discrimination.

When I’m 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.

○ Published & Forthcoming Papers

2026

Leveraging Genomic Data to Document Within-Race Attractiveness Penalties Among Black Americans

Beza Taddess^*, Luyin Zhang^*, and Sam Trejo^§. Forthcoming at Sociological Science. ●

Quantifying Direct Genetic Signal Captured by Principal Component Adjustment

Ramina Sotoudeh^*, Sam Trejo, Arbel Harpak, and Dalton Conley^§. Proceedings of the National Academy of Sciences.

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

Marissa Thompson, Sam Trejo, AJ Alvero, and Daphne Martschenko. 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. ●

2024

Using the Phenotype Differences Model to Identify Genetic Effects in Samples of Partially Genotyped Sibling Pairs

Sam Trejo and Klint Kanopka. Proceedings of the National Academy of Sciences. ●

The Effects of the Flint Water Crisis on the Educational Outcomes of School-Age Children

Sam Trejo, Gloria Yeomans-Maldonado, and Brian Jacob. Science Advances. ● ●

WASHINGTON POST I, WASHINGTON POST II, HARVARD PUBLIC HEALTH MAGAZINE, UNDARK MAGAZINE, PROPUBLICA, M-LIVE

Exploring the Fetal Origins Hypothesis Using Genetic Data

Sam Trejo. Social Forces. ●

*WINNER OF THE 2025 BEST PAPER AWARD (ASA BIOLOGY & SOCIETY SECTION)*

My School District Isn’t Segregated: Experimental Evidence on the Effect of Information on Parental Preferences Regarding School Segregation

Marissa Thompson^* and Sam Trejo^*. Sociology of Education. ● ● ●

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. ● ●

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 Health

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

2016

An Econometric Analysis of the Major Choice of First-Generation College Students

Sam Trejo. The Developing Economist. ●

● Resting Papers

Problems with a Causal Interpretation of Polygenic Score Differences between Jewish and non-Jewish Respondents in the Wisconsin Longitudinal Study

Jeremy Freese, Benjamin W. Domingue, Kamil Sicinski, Sam Trejo, and Pamela Herd. SocArXiv.

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