A few notes on The Creation of Patriarchy, by Gerda Lerner.

Bipedalism and upright posture led to smaller hips, causing humans to be born "premature", in order to facilitate birth, dexterity to hold babies and brain development of infants, who now have to learn culturally...

... - not by an innate instinct - how to survive. Meanwhile, human mothers, having a harder labour than other primates and an infant who is helpless and has to be carried around, wil move from foraging to gathering food for later consumption.

Instead of giving birth and being able to go forage for food moments later with an infant who can hold on to mother, and to do that whenever the mother is hungry, several times in a day, the human mother has to make the best of her next foraging, gathering more than one meal...

at a time, so the next time she needs to eat, food is already available for her. Also, it fostered social interaction among mothers, the creation of containers for food, tools to open and divide vegetables with children, or to dig for roots. Males continued to forage alone.

The human mother role - women's reproductive labour - was crucial to dexterity, brain development, the creation of culture to ensure their children's survival. Depending so much from mother created a fear from her. Failure to appeal to mother, causing indifference to her child...

... would mean certain death. From the necessity to care for helpless babies, the need to have several babies in order to secure at least two more humans who will reach adulthood, women may have willingly chosen economic activities compatible with their mothering,

the 1st division of labour arose out of biological determinant: the infant's' survival. But many arrangements could be made, away from the mythical narrative of the men hunter and women camp dweller. Thus "the link between childbearing and child-rearing for women is culturally..

... determined and subjected to social manipulation." With long and helpless human infancy comes a stronger mother-child bond. In a ever changing environment - prolonged drafts or enlargement of lakes, for instance - food would be scarce, the terrain more dangerous, making women

valuable for ensuring the survival of the whole species. Groups that failed to ensure that mothers bonded with their infants or didn't ensure that fertile women were alive and well would not survive. Gender was, then, created out of the fact that women do mothering of children.

Boys and girls learn to expect love from mother, but they can also associate women to fears of powerlessness. In order to find their identity, boys separate themselves from their mothers and associate with father and other males, girls have an identity because they can gestate

so they identify with their mothers because of the female potential to gestate. But gender-defined boys and girls are raised to accept gender roles situating women solely on reproduction. While human mothers had bonded with their infants and with other mothers for years...

men turned huntings of big-game prey their bonding ritual, where they went to hunt for animals, which brings a "boost" to nutrition, but also to build their "identities" (their ego), after being left in fear and awe of their mothers.