Asked by: Matthew Merton, Bournemouth

In the 1960s, zoologist Desmond Morris suggested that a woman’s lips evolved to signal sexual receptiveness, by mimicking increased blood flow to the genitalia. Research has shown that men do find the colour red attractive, but a 2012 study at the University of Kent found that men didn’t prefer a red vulva, specifically, over a pink one. So lip colour might just be a consequence of the thinner skin there, which improves sensitivity.

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