Sexual dimorphism exists to split evolutionary pressure and allow a species to both survive (conservative) and adapt to (risky) a changing environment. Human g

Sexual dimorphism exists to split evolutionary pressure and allow a species to both survive (conservative) and adapt to (risky) a changing environment. Human gender identities are several layers on top of this evolutionary foundation. In theory, they are needed to help socially indoctrinate people to what is now a successful meta model of behavior. They are progressively converging in terms of gender roles difference, not only because of societal and ideological changes of the last century, but as well because there are less severe crises, so that less of adaptive behavior is required.