Evolution in Childbirth

Anyone who’s given birth or been present for the process knows just what a tight squeeze it is for a baby’s head exiting the birth canal. There’s hardly any room to spare. Lots of other mammals have a lot more space relative to the baby’s head. Why haven’t humans adapted similarly over millennia? New analysis has found a kind of evolutionary trade-off –if women had larger birth canals, they’d likely suffer other serious problems. University of Vienna evolutionary anthropologist Nicole Grunstra worked on this study.