Family structure instability, genetic sensitivity, and child well-being.

The association between family structure instability and children's life chances is well documented, with children reared in stable, two-parent families experiencing more favorable outcomes than children in other family arrangements. This study examines father household entrances and exits, distinguishing between the entrance of a biological father and a social father and testing for interactions between family structure instability and children's age, gender, and genetic characteristics. Using data from the Fragile Families and Child Wellbeing Study and focusing on changes in family structure by age (years 0-9), the authors show that father exits are associated with increases in children's antisocial behavior, a strong predictor of health and well-being in adulthood. The pattern for father entrances is more complicated, with entrances for the biological father being associated with lower antisocial behavior among boys and social father entrances being associated with higher antisocial behavior. Child's age does not moderate the association; however, genetic information in the models sharpens the findings substantially.

Social disadvantage, genetic sensitivity, and children's telomere length.

Disadvantaged social environments are associated with adverse health outcomes. This has been attributed, in part, to chronic stress. Telomere length (TL) has been used as a biomarker of chronic stress: TL is shorter in adults in a variety of contexts, including disadvantaged social standing and depression. We use data from 40, 9-y-old boys participating in the Fragile Families and Child Wellbeing Study to extend this observation to African American children. We report that exposure to disadvantaged environments is associated with reduced TL by age 9 y. We document significant associations between low income, low maternal education, unstable family structure, and harsh parenting and TL. These effects were moderated by genetic variants in serotonergic and dopaminergic pathways. Consistent with the differential susceptibility hypothesis, subjects with the highest genetic sensitivity scores had the shortest TL when exposed to disadvantaged social environments and the longest TL when exposed to advantaged environments.

Genetic differential sensitivity to social environments: implications for research.

Researchers have proposed a genetic differential sensitivity to social environmental (GDSE) model positing that individuals with certain genetic makeups are more sensitive to favorable and unfavorable environmental influences than those without these genetic makeups. We discuss several issues facing researchers who want to use GDSE to examine health: (1) the need for greater theorizing about the social environment to properly understand the size and direction of environmental influences; (2) the potential for combining multiple genetic markers to measure an individual's genetic sensitivity to environmental influence; (3) how this model and exogenous shocks deal with gene-environment correlations; (4) implications of this model for public health and prevention; and (5) how life course and developmental theories may be used to inform GDSE research.

Role of mother's genes and environment in postpartum depression.

Most studies of human molecular genetics and social environment interactions on health have relied heavily on the classic diathesis-stress model that treats genetic variations and environments as being either "risky" or "protective." The biological susceptibility model posits that some individuals have greater genetic reactivity to stress, leading to worse outcomes in poor environments, but better outcomes in rich environments. Using a nontruncated measure of a chronic environmental stressor--socioeconomic status--measured by education, and two polymorphisms (5-HTTLPR and STin2 VNTR) of the serotonin transporter gene (5-HTT), we find strong evidence that some women are genetically more reactive to the environment, resulting in a crossover of risks of postpartum depression for the most reactive groups. We discuss how our approach and findings provide a framework for understanding some of the confusion in the gene-environment interaction literature on stress, 5-HTT, and depression.

Reflections on the incorporation of biomeasures into longitudinal social surveys: an international perspective.

This article is concerned with the underlying rationales for including biomeasures in longitudinal social surveys. In particular, it seeks to draw out the potential advantages of incorporating biomeasures in household panel studies for advancing our understanding of behaviors. A key emphasis is on elaborating pathways from biology through the brain/mind to behaviors and outcomes, particularly for social, demographic, economic, and health domains. The article elaborates these themes and illustrates them within the context of international experience. It lays out some of the key issues concerning conceptualization and operationalization of the integration of biomeasures into surveys. The next section considers the particular issues concerned with these opportunities and innovations for household panel studies. This is followed by a brief summary of the extent to which biomeasures have been incorporated into longitudinal social surveys, especially outside the United States. The final main section considers a wide range of strategic issues in the the collection of biomeasures in household panel studies and is followed by a brief conclusion.

The ABC of demographic behaviour: how the interplays of alleles, brains, and contexts over the life course should shape research aimed at understanding population processes.

This paper proposes core innovations in the strategy of research on demographic behaviour. One aim is a shift of attention away from events and towards a focus on dynamic processes and their interplay: away from a preoccupation with marriage and divorce, births, deaths, migrations, and household structure towards a broader perspective that takes account of partnership and intimacy, parenthood, potential and well-being, position in society and space, and personal ties. Another aim is a much closer engagement with genetics, neuroscience, psychology, and behavioural economics. A third aim is a strategy that pays more attention to pathways within the individual, to the processes entailed when the individual interacts with various contexts, and to progressions that involve the interplay of the pathways and processes through the life course. These shifts of emphasis, which have already begun to occur, require a systematic reassessment of priorities for research on demographic behaviour.

Parental divorce and subsequent disadvantage: a cross-cohort comparison.

Although many studies have examined the link between parental divorce and subsequent well-being, some theories of the effects of divorce suggest that the negative associations should have declined over time. However, few studies have examined the extent to which the associations have remained stable over time. Using data from two British cohorts, we analyzed both shorter- and longer-term outcomes of children who experienced parental divorce and the extent to which the associations have changed over time. Estimating similar models for both cohorts, we found little evidence of any change in the size of the relationship as divorce became more commonplace.

Discussion of paper 'explanations of the fertility crisis in modern societies: a search for commonalities', Population Studies 57(3): 241-263, by John Caldwell and Thomas Schindlmayr.

The contributors to this discussion were invited to submit comments, each from a different standpoint, on the paper by John Caldwell and Thomas Schindlmayr that appeared in the preceding issue of the journal. The invitation was issued with the approval of these authors, and the journal is grateful to them for allowing their paper to be used to generate debate on the issues they had raised. The discussion is followed by the authors' response to it.