Pages

Wednesday, September 5, 2012

Why Pregnancy Really Lasts 9 Months



Human babies are born helpless and needy, a fact that anthropologists have long explained by pointing to the size of the female pelvis. If babies were born with bigger brains, the theory goes, they'd get stuck in the birth canal. Instead, they stop gestating before they grow too large, resulting in completely dependent newborns.




No comments:

Post a Comment