Research > Research Themes > Human Resources and Endowments > Genes and gene-environment interactions in population processes

Increasing information is available on genetic endowments, through either direct measurement (Schurr), clinical or cohort studies (Ewbank), or indirectly through statistics-based inference (Kohler, Behrman). In the Journal of the American Statistical Association, Rosenbaum links the sibship transmission/disequilibrium design in genetic epidemiology to related models of causal processes. A general theoretical understanding is emerging that the effects of genes on health and behavior do not so much compete with resource inputs and other endowments, but can in some circumstances have differential effects depending on the social and physical environment. Kohler has especially taken this perspective in several articles on fertility, with key papers in Population & Development Review (with J. Rodgers, Behrman, and others): Danish twin data suggest that genetic influences on fertility exist, but that their relative magnitude and pattern is contingent on gender and on the socio-economic environment experienced by cohorts. Because genetic effects are most prevalent in situations with consciously controlled fertility and relatively egalitarian opportunities, the genetic dispositions affect primarily fertility behavior and motivations for having children. These motivations include subjective well-being. The impetus toward fertility improves well-being for a first-child, but subsequent fertility has no effect (for males) and is deleterious (for females), which is a reminder that genetic imperatives interact with social constructions. In contrast, Ewbank’s results for APOE and mortality show no such interactions.