Assessment of genetic and environmental influences on differential ratings of within-family experiences and relationships in twins.

ABSTRACT

BACKGROUND: Although there is evidence that genetic factors influence individual differences in environmental risk exposure, there are few findings on genetic effects on differential parenting. The present study sought to examine this issue. METHODS: The sample comprised 1,117 pairs of like-sex male and female twins, aged 8-16 years, and their parents, recruited from the school population of Virginia. Differential ratings of the within-family experiences were provided by the Twin Inventory of Relationships and Experiences (TIRE). RESULTS: Dimensions describing the within-family environment based on differential ratings contrasting the twins with one another, were influenced, to an approximately equal extent, by both genetic and environmental factors. CONCLUSIONS: The findings suggest that genetic differences between like-sex siblings lead them to experience their family environment differently, but also that environmental influences significantly affect interactions within the family.