Human babies have big brains. But mothers have narrow hips as we walk on 2 legs.
So baby can't stay inside till the brain is fully grown.
Baby has to come out early.
That's why human babies are born unfinished !!!!
When human babies are born, their brain is only 25% done. The rest grows after birth.
For the first year, human babies need mom/dad for everything.
But other primates ' babies stay inside the body for longer time. When they are born, their brain is already more grown. So they can hold on, crawl and cling right away !!!
So this difference make human babies so helpless because of unfinished brain !!!