One of the penalties of walking on two feet as opposed to the usual mammalian four is the size of the pelvis.
With body weight and locomotion focused in the middle of the body the birth canal tended to be reduced. An alternative was that Homo sapiens developed a duck-like waddle as did earlier hominins such as Australopithecus. Humans want to be elegant. The gorillas took the Soviet tank approach and Homo sapiens in order to avoid being cat-food, reckoned that being fleet of foot was a good thing as well as standing upright to observe and avoid danger on the savannah.
By contrast Homo heidleburgensis, an immediate forerunner of H sapiens was tall and built very robustly both in jaw and muscle attachments hence a real tough guy.
But back to the point; with the small pelvis, giving birth was not easy for the more graceful human ape. Remembering that natural selection filters out the losers in evolutionary change the only successful breeding mothers were those favoured with giving birth to immature young. The consequence was that humans require infinitely more assistance to be nurtured from a state of complete helplessness and still require help to survive for the first ten or so years.
The upshot of these compromises including large brain and less brawn and the need to be born small was that H sapiens used intelligence to hunt for meat and kept out of danger whilst the mothers bonded emotionally with their helpless offspring for an extended period, allowing for a family and social sense to develop in the child.
Behold: the modern human! Being so recent however, around only two hundred thousand years, it seems to me we still have a long way to sort out the nature of the human animal and put aggression behind us.
Why are we still here? Because we have flexible thinking which employs imagination to project a future so we can make strategies. Our imagination makes us human but also subjects us to the weakness of assuming our imagination represents truth.