Using the biological and adoptive families in the Minnesota-based Sibling Interaction and Behavior Study, we investigated the associations among genetic and environmental influences on IQ, parenting, parental expectations for offspring educational attainment, engagement in school, and school grades. All variables showed substantial genetic influence, and very modest shared environmental influence. No gender differences were evident. There were significant genetic influences common to IQ and parental expectations of educational attainment, parenting and engagement in school, school grades and engagement in school, parental expectations for offspring educational attainment and school grades, and IQ and school grades. A possible interpretation of the common genetic influences involving parenting is that parents use their own experience with school in shaping the ways in which they parent their offspring.
Bibliographical noteFunding Information:
This research was supported by US Public Health Service Grants #AA11186 and MH66140 to Matt McGue and William G. Iacono. Wendy Johnson was also supported by a University of Minnesota doctoral dissertation fellowship. We thank the siblings and their families and the recruiting, interviewing, data management, and lab staffs of the Sibling Interaction and Behavior Study.
- Adoption study
- Gender differences
- Genetic and environmental influences
- Parent expectations
- School engagement
- School grades