Scientific discourse on race has always intertwined race and sex difference.

Evidence

These three approaches reveal in different ways how thinking about race difference has always been permeated by a focus on sex difference also. The critics of “natural race” have approached this topic through, for example, analyses of scientific uses of race/sex analogies, of the manipulation of reproductive practices to preserve racial and culturally valued sexual differences, and of primate studies that have been used to generate scientific arguments for the service of racial and sexual sterotypes to racist, colonial, and androcentric projects (Hammonds, forthcoming; Haraway, 1989; Stepan, 1986). — David Theo Goldberg, John Solomos, A Companion to Racial and Ethnic Studies, 1567