Why do men love breasts? In BLONDES I describe the most interesting and promising theories — from the Freudian (breasts remind men of Mom) to the evolutionary (breasts resemble buttocks and prehuman ancestors mounted from behind), and the reproductive (breasts are an indicator of age and big breasts are a marker of high estrogen levels). These are some of the most likely reasons why breasts are beloved even in cultures that don’t eroticize them any more than the face.

A new spin on the male fascination with breasts came up this week in John Tierney's interview with neuroscientist Larry Young on love blockers. According to Young, “more frequent sex and more attention to breasts could help build long-term bonds through a ‘cocktail of ancient neuropeptides,’ like the oxytocin released during foreplay or orgasm.” The same oxytocin circuit, he notes, is activated when a woman nurses her infant.

The article doesn’t connect all the dots, but the suggestion is as follows: The hormone oxytocin is released when breastfeeding, making the mother feel good and helping her bond with baby. Sucking and caressing a woman’s breasts during foreplay may also trigger oxytocin release. When oxytocin hits the brain, women become more trusting and attached. Men evolved to pay attention to breasts as a means of attracting and retaining lovers.

The “boobs help bonding” theory may not be the strongest explanation of why men love breasts, but it’s worth introducing to the debate. That said, I strongly suspect that there are many women out there for whom a lover’s suckling does nothing — and there are many breast-ogling guys who know nothing of foreplay.