Professor Robert Plomin, a behavioral geneticist at King's College London, explains in this fascinating Guardian podcast that genes explain about 60% of differences between children in educational achievement. It applies to all areas, from math to humanities.
These differences show up very early, as early as 4 years old. Different schools or teaching methods explain at most 20%. Plomin notes that educator training materials which tout unproven educational methods are worthless. And sets out a program for genetically screening children to direct educational resources at those who most need them, in a personalized manner.
He is the co-author of G is for Genes: The Impact of Genetics on Educations and Achievement.