[H]ow should we prepare for the likelihood that in the coming years, genetic studies will show that behavioral or cognitive traits are influenced by genetic variation, and that these traits will differ on average cross human populations, both with regard to their average and their variation within populations? Even if we do not yet know what those differences will be, we need to come up with a new way of thinking that can accommodate such differences, rather than deny categorically that differences can exist and so find ourselves caught without a strategy once they are found.
It would be tempting, in the wake of the genome revolution, to settle on a new comforting platitude, invoking the history of repeated admixture in the human past as an argument for population differences being meaningless. But such a statement is wrongheaded, as if we were to randomly pick two people living in the world today, we would find that many of the population lineages contributing to them have been isolated from each other for long enough that there has been ample opportunity for substantial average biological differences to arise between them. The right way to deal with the inevitable discovery of substantial differences across populations is to realize that their existence should not affect the way we conduct ourselves. As a society we should commit to according everyone equal rights despite the differences that exist among individuals. If we aspire to treat all individuals with respect regardless of the extraordinary differences that exist among individuals within a population, it should not be so much more of an effort to accommodate the smaller but still significant average differences across populations.
David Reich, Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past, New York, 2018, p. 265