The document discusses the differences between sex and gender. Sex refers to biological attributes that distinguish males and females, such as reproductive organs and secondary sex characteristics. Gender refers to cultural attributes that arise from biological sex differences, such as gender roles, behaviors, and styles of dress. The document then examines gender differences in various societies, including divisions of labor between males and females, as well as cultural rules around sexual behavior and taboos such as incest. Possible explanations for gender norms, such as compatibility with childcare responsibilities, are also explored.