Theories abound as to why breasts are man magnets: they advertise fertility.

They’re a sign of sexual maturity. They’re just fun to look at and feel. But Dr Larry Young, a professor of psychiatry at Emory University and the author of The Chemistry Between Us argues that breasts are built for emotional connection. Breastfeeding triggers the release of the bonding hormone, oxytocin; sex (which involves breast play, of course) provokes the same response, which strengthens the union between partners. “Most animals go their separate ways after sex,” says Young.

“But it’s adaptive for humans to form relationships. Sex is not only for reproduction but also to stimulate bonding.”