Larry Young, PhD and Brian Alexander researched the matter for their new book The Chemistry Between Us: Love, Sex, and the Science of Attraction, and shared some of their thoughts for The Huffington Post.
"Biologically speaking, this human male breast obsession is pretty weird," they wrote. "Men are the only male mammals fascinated by breasts in a sexual context.
"We are also the only species in which males caress, massage and even orally stimulate the female breasts during foreplay and sex.
"Men are extremely drawn to breasts, and not because boys learn on the playground that breasts are something that they should be interested in. It's biological and deeply ingrained in our brain."
Young and Alexander believe that it's all "neurological" and that the obsession stems from a mother's bond with her child.
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"When a woman gives birth, her newborn will engage in some pretty elaborate manipulations of its mother's breasts," they stated. "This stimulation sends signals along nerves and into the brain.
"This oxytocin release eventually stimulates smooth muscles in a woman's breasts to eject milk, making it available to her nursing baby."
The authors added: "But oxytocin release has other effects, too. When released at the baby's instigation, the attention of the mother focuses on her baby. The infant becomes the most important thing in the world.
"Oxytocin, acting in concert with dopamine, also helps imprint the newborn's face, smell and sounds in the mother's reward circuitry, making nursing and nurturing a feel-good experience, motivating her to keep doing it and forging the mother-infant bond.
"This bond is not only the most beautiful of all social bonds, it can also be the most enduring, lasting a lifetime."
Do you agree? Why do you think men are obsessed with breasts? Leave your comments below!