Risk of Caesarean section is heritable-Natural selection cannot reduce the rates of obstructed labour
(PHYSorg.com Biology)

During the last decades, rates of Caesarean section have multiplied; by now it is one of the most frequently performed surgical treatments worldwide. Even if many of these C-sections are not strictly medically indicated, human childbirth is complicated and risky compared to that in other primates. Why has evolution by natural selection not led to a wider birth canal, thus reducing the high rates of obstructed labor?