Gender can be a continuous variable, not just a categorical one: Comment on Hyde, Bigler, Joel, Tate, and van Anders (2019).

Hyde, Bigler, Joel, Tate, and van Anders (2019) opened debate on the treatment by psychologists and researchers of sex-gender as a dichotomous variable (male-female) and the utility of alternative conceptions. In doing so though, they framed the alternative to a gender-binary as treating gender as a categorical variable. Hyde et al.'s review obscures important contributions of a large number of psychological researchers who for decades have treated gender as a continuous variable. Their work offers a forceful contrast to the traditional gender-binary approach and also has a direct bearing on some of the questions raised by Hyde et al., including gender differences in prevalence of depression. (PsycINFO Database Record (c) 2019 APA, all rights reserved).