The explosion of research on issues of sex and gender globally provides massive evidence refuting essentialist claims. Research does not discount the role of biology in gender development, but it clearly demonstrates that culture is a greater barrier to equality than biology. When desire and talent are combined with opportunity and encouragement, people can move into the “traditional” gender role of the other. When such movement becomes widespread, gender distinctions are blurred. Decades of research make it empirically clear that the benefits of equality for males and females alike far outweigh the disadvantages.