The basis of our binary system is the heteronormativity: we are all presumably cis-heterosexual.
CIS are people who identify with the gender they were assigned at birth. That is, girls with female sexed characters and boys with male sexed characters.
HETEROSEXUALS (or straight people) are boys who like girls and girls who like boys.
The reason why heteronormativity does not admit anything that has to do with trans or queer is because it would mean recognizing that there are realities outside the hegemonic. And, from this axiom (women and men are cisheterosexual until proven otherwise), two gender frames are generated, two sets of ideas about what is considered expected and acceptable behaviour on women and on men.
Furthermore, since, from this point of view, we are expected to pair up in straight couples, masculine and feminine are understood as opposites. An approach that, at the same time, causes inequality to be seen as natural. In this sense, all elements of popular culture and formal education work to create men and women from “templates” that complement each other.
Thus, to sum it up in one sentence, HETERONORMATIVITY and binarism are the ones to look at if we want to understand why women and men develop different personality traits, abilities and deficiencies.
