Genetics and Child Development: Recent Advances and Their Implications for Developmental Research

Recent genetic discoveries offer a new lens through which to study cognitive, emotional, behavioral, and social processes that are foundational to children’s development. In this article, we review the latest advances in genomics—genome-wide association studies and the polygenic scores that have come out of them—and discuss how these techniques can be leveraged to shed light on developmental research questions. Then, we describe how developmental scientists might apply these methods in their own lines of work—for example, in investigations of individual differences in developmental trajectories, intergenerational transmission, peer relationships, and processes of resilience and positive adaptation. Finally, we discuss ethical concerns and limitations of genetics research as they pertain to developmental science. KEYWORDS—child development; education; genetics; individual differences; polygenic scores Developmental psychologists have grappled with several key questions for decades: Which factors shape individual differences in children’s developmental trajectories? How do parents influence children and transmit traits across generations? How can environments be modified to promote children’s positive adaptation and reduce inequalities? Recent methodological advances in genetics—namely, polygenic scores—offer a new lens through which to study these developmental processes by shedding light on the cognitive, emotional, behavioral, and social processes that underlie children’s development. In this article, we review how polygenic scores can be integrated into developmental science to study questions about children’s and adolescents’ development. Building on other recent reviews about polygenic scores (Belsky & Harden, 2019; Harden & Koellinger, 2020), we provide an overview tailored to developmental scientists by focusing on child and adolescent development before age 18 and discuss how genetic methods can be applied to questions uniquely relevant to developmental scientists. First, we review recent research that has created and used polygenic scores to study social science outcomes. Then, we describe how developmental psychologists across diverse subspecialties might apply polygenic-score methods in their own lines of work. We conclude by discussing the limitations and ethical concerns in this emerging area of research. NEWDISCOVERIES IN BEHAVIORAL GENETICS Studies of twins and children who have been adopted have a long history in developmental psychology, and provided initial evidence that virtually all traits are partially influenced by genes (Matthews & Turkheimer, 2019; Plomin, 2019; Silventoinen et al., 2020). These studies compare individuals who differ in genetic relatedness (e.g., identical versus fraternal twins) to investigate the relative influence of genes versus environments. More recently, the plummeting cost of genotyping has made it possible to study genetic influences by directly measuring DNA. It is now feasible to measure (i.e., to genotype) millions of genetic variants in a few hours for less than $100. In psychological research, genotyping was initially used to investigate associations between specific candidate genes and traits of interest. However, focusing on a limited set of candidate genes has proved largely ill-advised, with many findings failing to replicate. This replication failure occurred in part because Emma Armstrong-Carter, Stanford University; Jasmin Wertz, Duke University; Benjamin W. Domingue, Stanford University. Emma Armstrong-Carter is supported by the Institute of Education Sciences Fellowship Training Grant (R305B140009). Jasmin Wertz is supported by a postdoctoral fellowship from the AXA Research Fund. Thank you to Rosa Cheesman, Sara Jaffee, Rachel Romeo, and Sabine Doebel for comments on an earlier version of this article. Correspondence concerning this article should be addressed to Emma Armstrong-Carter, CERAS #452, 520 Galvez Mall, Stanford, CA 94305; e-mail: emmaac@stanford.edu. © 2021 Society for Research in Child Development DOI: 10.1111/cdep.12400 Volume 0, Number 0, 2021, Pages 1–8 CHILD DEVELOPMENT PERSPECTIVES