Marital adjustment as a moderator for genetic and environmental influences on parenting

Abstract

Family systems theory proposes that the parent-child relationship is embedded within the broader system of the family, and that other family subsystems can influence the dynamics and quality of the parent-child relationship. The current paper examines marital adjustment as a context for the parent-child relationship during adolescence. Specifically, the extent to which marital adjustment moderates child-based genetic and environmental effects on the parent-child relationship was assessed. Data for this study were from the initial wave of the Nonshared Environment in Adolescent Development (NEAD) study, and included 720 families with same-sex sibling pairs, ages 10-18 years. A range of sibling and family types was sampled, with 93 monozygotic twin pairs, 99 dizygotic twin pairs, and 95 sibling pairs from nondivorced families, and 182 sibling, 109 half-sibling, and 130 unrelated sibling pairs from stepfamilies. Composite measures of marriage (based on parent reports) and parenting (based child and parent reports and observation ratings) were examined. Results indicate that as marital adjustment declines, evocative child effects on parenting increase, while the role of shared family experiences declines. However, the specific impact of marital adjustment on child-based genetic and child-specific nonshared environmental contributions to parenting differed for mothers and fathers. This study identifies a previously unexplored mechanism through which family subsystems influence each other.

Figure 1:

Path diagram for the GxE interaction model: a, c, and e= unmoderated genetic, common environment, and nonshared environment components; β_X, β_Y, and β_Z = moderated components of a, c, and e, respectively. β_M = main effect of the moderator; μ= grand mean; M= level of moderator variable (marital adjustment). Correlations between genetic terms (A) is assumed to be r = 1 for MZ twins, r = .5 for DZ twins and full siblings, r = .25 for half siblings, and r = 0 for unrelated step-sibling. Correlations between shared environmental terms (C) are 1.0 for all sibling types.

Figure 2:

Unstandardized contributions of genetic (A), shared environmental (C), and nonshared environmental (E) influences to variance in negative parenting graphed as a function of increasing standard deviations of marital quality. Total residual variance is amount of variance in negative parenting not accounted for by main effects of the moderator variable (marital quality).