While each society has its own gender roles, there are a few roles that universally belong squarely to either of the sexes. Apart from the Maasai, who thought their women were strong enough to build houses and look after cattle, most communities will have men take up duties that require physical strength and leave the females to cook, clean and take care of the home.
Women are expected to be nurturers because nature has bestowed on them the role of carrying babies within them. Females across species, with the exception of the birds, take an active role in the upbringing of their young ones during the formative stage and beyond.