Parental education moderates genetic influences on reading disability.

Environmental moderation of the level of genetic influence on children's reading disabilities was explored in a sample of 545 identical and fraternal twins (mean age = 11.5 years). Parents' number of years of education, which is correlated with a broad range of environmental factors related to reading development, was significantly related to the level of genetic influence on reading disability. Genetic influence was higher and environmental influence was lower among children whose parents had a high level of education, compared with children whose parents had a lower level of education. We discuss the implications of these results for behavior genetic and molecular genetic research, for the diagnosis and remediation of reading disabilities, and for policy in public education.