Research into the intergenerational transmission of educational advantage has long been criticized for not paying sufficient attention to genetics. This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa) and administrative register data on 25000 genotyped Norwegian children and their parents. We assess and disentangle the relative importance of genetics and social background for children's standardized academic test scores. Norway offers a particularly interesting context for intergenerational transmission, as the welfare state and educational system is designed to provide equal opportunity structures for children. The results point to genetics only confounding the parent status-offspring achievement relationship to a small degree, to 'genetic nurture' effects being small, and pro-vide no evidence of neither Scarr-Rowe interactions in test scores nor parent-child genotype interactions. Even in a universal welfare state with relatively low levels of inequality, there are two systems of ascription, one genetic and one social, and these are largely independent of each other. [Additional funds for the report provided by the Stiftelsen Kristian Gerhard Jebsen (Norway), Trond Mohn Foundation (Norway), Novo Nordisk Foundation (Denmark), University of Bergen (Norway), South-Eastern Norway Regional Health Authority, and Western Norway Regional Health Authority. The Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research (Norway).]