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 × 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. Copyright © 2007 John Wiley & Sons, Ltd.