Birth Risk Factors Predict Identical Twin Differences in Exposure to Harsh Parenting

• In Event: 1-072 - Gene-Environment Correlations As Critical Influences on Children’s Social Relationships

Integrative Statement

The family environment influences children’s development, and children’s individual attributes also influence parenting, through bidirectional parent-child relationship processes (Zvara, Sheppard, & Cox, 2018). Children with more individual risk factors (e.g., poorer self-regulation, “difficult” temperament, poorer language/communication skills) also are less likely to elicit and receive optimal caregiving (Dennis, Neese, & Fenning, 2018). Because sibling children differ in their attributes and developmental trajectories, there is substantial evidence showing “child-specific” parenting behaviors that differ within (as well as between) families (Plamondon et al., 2018). However, it is not yet known whether these child-specific parenting experiences have roots from the beginning of life—specifically, whether they arise in part from sibling differences in developmental risk factors at birth (i.e., birthweight, premature birth). Furthermore, until recently, the evidence regarding the role of birth risks on subsequent parenting environments has not distinguished child-specific experiences within versus between families. However, a just-published sibling analysis tackled this gap, showing that within pairs of siblings, the sibling with a higher birth weight received more sensitive maternal care in early childhood (Browne, Wade, et al., 2018).

In the current study, we sought to replicate and extend this recent important finding, by also controlling for genetic effects on sibling differences that are confounded with child-behavioral and parenting-environmental differences within families. We also tested the potential interactive effect of birthweight and gestation length, given that these two birth risk factors may interact in longitudinal prediction of developmental outcomes and parenting environments (Deater-Deckard, 2016). We used an identical twin differences design to test the hypothesis that it is the combination of low birth weight (relative to co-twin) and short gestation that will most strongly predict child-specific parenting environment (relative to co-twin), even within genetically identical twin pairs. Specifically, within dyads, the smaller twin is expected to be the recipient of less positive or more negative parenting relative to the co-twin, and this effect is anticipated to be strongest for premature births. The sample included 114 identical twin pairs, assessed three times (5-7yrs; composite scores analyzed) for parent-rated and observer-rated parenting. Highly reliable composite scores representing child-specific positive (e.g., warmth, responsiveness) and negative (e.g., harsh, intrusive) parenting behaviors were computed. A regression model was used to predict twin relative difference scores in parenting (separately for positive and negative parenting). The interaction effect was in the expected direction but significant only for negative parenting, β = .16, one-tailed p < .05. Post-hoc probing showed that among premature births only (i.e., 1 to 2 SD below mean, about 28-32 weeks gestation), the smaller twin received more negative parenting at 5-7yrs of age compared to the genetically identical co-twin; β = -.34 to .52, p < .05. For average or longer-term pregnancies (i.e., 33+ weeks), the association was near zero and nonsignificant. Results provide stronger evidence of birth risk factors’ interactive effects on children’s child-specific parenting environments, even when controlling for genetic differences.

Authors

• Kirby Deater-Deckard, University Massachusetts
  Presenting Author

• Lisabeth Fisher DiLalla, Southern Illinois University School of Medicine
  Non-Presenting Author

• Lee Thompson, Case Western Reserve University
  Non-Presenting Author

• Stephen Petrill, The Ohio State University
  Non-Presenting Author