The role of parental genotype in predicting offspring years
of education: evidence for genetic nurture
Similarities between parent and offspring are widespread in psychology; however, shared genetic variants often confound
causal inference for offspring outcomes. A polygenic score (PGS) derived from genome-wide association studies (GWAS)
can be used to test for the presence of parental influence that controls for genetic variants shared across generations. We use a
PGS for educational attainment (EA3; N ≈ 750 thousand) to predict offspring years of education in a sample of 2517 twins
and both parents. We find that within families, the dizygotic twin with the higher PGS is more likely to attain higher
education (unstandardized β = 0.32; p < 0.001). Additionally, however, we find an effect of parental genotype on offspring
outcome that is independent of the offspring’s own genotype; this raises the variance explained in offspring years of
education from 9.3 to 11.1% (ΔR2 = 0.018, p < 0.001). Controlling for parental IQ or socioeconomic status substantially
attenuated or eliminated this effect of parental genotype. These findings suggest a role of environmental factors affected by
heritable characteristics of the parents in fostering offspring years of education.