. . . is evident at birth, enlarges at puberty, and continues into maturity. The perception of sex is mainly a function of sexual dimorphism. The attribution of gender is based on perceived sex, i.e., body features (plus, cultural cues, hairstyle, clothing, cosmetics, and behavior) . . .
Several answers . . . http://www.originalplumbing.com/index.php/the-basics/video/item/880-wtf-is-gender
We make gender every day. We only need to look back, say, thirty years to see how things have changed. Gender comes mostly from us, the architects of human culture.