We introduce a novel strategy to study the intergenerational transmission of human capital skills, net of genetic skill transfers. For this purpose, we use unique Danish data on children conceived through sperm and egg donation in IVF treatments to estimate the relationship between child test scores and parental years of schooling. Because the assignment of donors is not selective, these parental schooling estimates allow for a causal nurture interpretation. Once we take account of genes, we find that only the education of mothers matters: the association between father’s education and child test scores (in reading and math) is insignificant and practically zero, whereas the association between mother’s education and child test scores (in reading, not in math) is significant and large, and as large as the association we estimate for mothers of non-donor children.