An abridged version of this article was published last month in Cherwell, the Oxford University student newspaper. You can read that version here.
In October 2016 a research paper prompted widespread news reports that caesarean sections are affecting human evolution by causing the size of newborns to increase. Larger babies which, in the past, would have died from obstructed labour, are now able to survive. The alleles—gene variants—that cause this obstructive ‘fetopelvic disproportion’ (FPD) are no longer selected against and are, it is claimed, becoming more prevalent in the human population. However, the story was massively over-hyped, as the researchers did not find solid evidence that this is actually happening.