Reply to Grossman: The role of natural selection for the increase of Caesarean section rates

Recently, we presented the “cliff-edge model” (1) to explain why natural selection has not reduced the high rates of fetopelvic disproportion (FPD) in childbirth. This evolutionary model predicts that birth-relevant anatomical dimensions have changed in response to the regular use of Caesarean sections (C-sections). Grossman’s (2) interesting comment on our report allows us to clarify several issues. As noted by Grossmann (2), we present a theoretical model, not empirical data, for this recent evolutionary change. Medical treatment has systematically changed survival rates and thus, by definition, the selective regime faced by modern humans. Hence, an evolutionary change of anatomical properties is not surprising. In … [↵][1]1To whom correspondence should be addressed. Email: philipp.mitteroecker{at}univie.ac.at. [1]: #xref-corresp-1-1