Much of the controversy stemmed from Chapters 13 and 14, where the authors write about the enduring differences in race and intelligence and discuss implications of that difference. They write in the introduction to Chapter 13 that "The debate about whether and how much genes and environment have to do with ethnic differences remains unresolved," and that "It seems highly likely to us that both genes and the environment have something to do with racial differences." This stands in contrast to the contemporary and subsequent consensus of mainstream researchers, who do not find that racial disparities in educational attainment or measured intelligence are explained by between-group genetic differences.