" I have a theory that all human babies are born prematurely. Given the human life span – three score years and ten – to be comparable with other animals of similar longevity, human gestation should be about two years. But the human head is so big by the age of two that no woman could deliver it. So our babies are born prematurely, in a state of utter helplessness. "

― Jennifer Worth , The Midwife: A Memoir of Birth, Joy, and Hard Times