Evidence from intervention studies, quantitative genetic and molecular genetic studies suggests that genetic, and to a lesser extent, shared environmental influences are important to the development of reading and related cognitive skills. The Northeast-Northwest Collaborative Adoption Projects (N2CAP) is a sample of 241 adoptive families, containing 354 children and their adoptive parents. Negative parent outcome x child age interactions significantly predicted child outcomes, suggesting that shared environmental influences related to parent-offspring resemblance, although modest, are most salient in younger children. Additional analyses suggested that identified measures of the family environment largely accounted for these parent-offspring correlations. (Contains 7 tables and 2 figures.)