These gender stereotypes operate throughout life both as expectations about the characteristics men and women have, and as gender norms dictating double standards for how women and men should behave, influencing people’s interests, self-concept, performance, and beliefs about capabilities in gendered domains. These gender stereotypes and norms are also the foundation of both conscious and unconscious forms of sex discrimination, like biased evaluations of performance and potential, and social and economic backlash against people whose behaviour isn’t in line with them.65 Gender stereotypes and norms can certainly harm and constrain boys and men too. But gender is a hierarchy. The higher prestige of males and masculinity is, some have speculated, why significant numbers of girls in middle childhood start to shun the “girl” toys and activities they have supposedly evolved to prefer, in order to become “one of the boys,” while there is a conspicuous absence of boys hoping to become “one of the girls.”66