The most important point about equality of opportunity from a genetic perspective is that equality of opportunity does not translate to equality of outcome. If educational opportunities were the same for all children, would their outcomes be the same in terms of school achievement? The answer is clearly ‘no’ because even if environmental differences were eliminated genetic differences would remain. What follows from this point is one of the most extraordinary implications of genetics. Instead of genetics being antithetical to equal opportunity, heritability of outcomes can be seen as an index of equality of opportunity. Equal opportunity means that environmental advantages and disadvantages such as privilege and prejudice have little effect on outcomes. Individual differences in outcomes that remain after systematic environmental biases are diminished are to a greater extent due to genetic differences. In this way, greater educational equality of opportunity results in greater heritability of school would be 0. Finding that heritability of school achievement is higher than for most traits, about 60 per cent, suggests that there is substantial equality of opportunity.

Robert Plomin, Blueprint: How DNA makes us who we are, Cambridge, Massachusetts, 2018, p. 110