Why do straight men dedicate so much thought to breasts? These fatty tissues hanging from women’s chests seem to hold an inexplicable allure for many men. While scientists haven’t pinpointed a single definitive reason for this widespread male breast fixation, various theories attempt to unravel this intriguing phenomenon. Let’s embark on a journey through the captivating speculations surrounding the human bosom and explore why understanding the allure of breasts is such a complex puzzle.
Mammary glands are a defining characteristic of mammals, yet humans appear unique in assigning a significant sexual role to breasts. It’s not that nipple interest is entirely absent in the animal kingdom. As noted in “Biological Exuberance: Animal Homosexuality and Natural Diversity,” some primates, like bonobos, have been observed stimulating their own nipples during masturbation. However, face-to-face mating, common in humans, is rare in most mammals, making nipple stimulation less relevant in their sexual behavior.
Researchers have long proposed that the development of fatty deposits around female mammary glands in humans evolved for sexual signaling purposes. Anthropologist Owen Lovejoy theorized that evolution strategically highlighted reproductive organs, both male and female, to foster pair bonding. This evolutionary push not only shaped female breasts but also contributed to men developing comparatively larger penises in proportion to their body size.
Another prevalent theory suggests that breasts evolved to signal a woman’s nutritional status and youthfulness to potential mates. Studies indicating men’s preference for larger breasts and a high waist-to-hip ratio support the idea that an hourglass figure conveys youth and fertility. A 2004 study published in the Proceedings of the Royal Society B even discovered that women with larger breasts tend to have higher levels of estradiol mid-cycle, potentially indicating increased fertility.
Nature vs. Nurture in Breast Attraction
However, the universality of breast adoration is not definitively established. A 1951 study spanning 191 cultures by anthropologists Clellan Ford and ethologist Frank Beach revealed that breasts were considered sexually significant to men in only 13 of these cultures. Among those, nine cultures favored large breasts. The Azande and Ganda of Africa found long, pendulous breasts most attractive, while the Maasai of Africa and Manus of the South Pacific preferred upright, hemispherical breasts, not necessarily large ones. Breast stimulation during sex was reported in 13 cultures, but only three overlapped with societies where men considered breasts crucial for sexual attraction.
Cultural anthropologist Katherine Dettwyler, in a chapter of “Breastfeeding: Biocultural Perspectives,” recounts sharing information about sexual foreplay involving breasts with friends in Mali. The reactions ranged from bewilderment to horror.
Dettwyler wrote, “In any case, they regarded it as unnatural, perverted behavior, and found it difficult to believe that men would become sexually aroused by women’s breasts, or that women would find such activities pleasurable.”
This cultural perspective suggests that men’s attraction to breasts might be less about biological predisposition and more about learned behavior, shaped by cultural conditioning from a young age.
Dettwyler further noted, “Obviously, humans can learn to view breasts as sexually attractive. We can learn to prefer long, pendulous breasts, or upright, hemispherical breasts. We can learn to prefer large breasts.”
Even if biological factors contribute to breast attraction, cultural variations likely play a role. A 2011 study comparing men’s preferences for breast size, symmetry, and areola characteristics across Papua New Guinea, Samoa, and New Zealand, found that men from Papua New Guinea favored larger breasts compared to men from the other two islands. The researchers proposed that in subsistence cultures like Papua New Guinea, fuller figures, including breasts, could signal a woman’s access to resources, important for pregnancy and childcare. Areola preferences varied significantly across cultures, indicating culturally specific ideals.
Breasts as a Sexual Byproduct?
The primary biological function of breasts is, of course, infant nourishment. Some researchers propose that sexual interest in breasts may have evolved by leveraging the pre-existing neural pathways associated with breastfeeding for a different purpose: pair bonding.
Larry Young, a psychiatry professor at Emory University specializing in the neurobiological basis of social behaviors, suggests that human evolution has repurposed an ancient neural circuit initially designed to strengthen the mother-infant bond during breastfeeding. This same circuitry may now contribute to strengthening bonds between couples. In this view, men’s attraction to breasts mirrors a baby’s innate draw to them.
During breastfeeding, nipple stimulation triggers the release of oxytocin, often called the “love hormone,” in a woman’s brain. Oxytocin promotes focused attention and affection towards her baby. However, recent research indicates that this neural pathway isn’t exclusive to mother-infant bonding in humans.
Studies have shown that nipple stimulation enhances sexual arousal in the majority of women, activating brain regions similar to those stimulated by vaginal and clitoral stimulation. When a partner touches, massages, or kisses a woman’s breasts, it can trigger oxytocin release in her brain, similar to breastfeeding. In a sexual context, oxytocin can focus a woman’s attention and affection on her partner, strengthening their bond.
In essence, men might enhance their desirability by stimulating a woman’s breasts during intimacy. Evolution may have instilled this desire in men. Young believes this theory offers a compelling explanation. He elaborated on this in his book, “The Chemistry Between Us,” co-authored with Brian Alexander.
Young explained that attraction to breasts is “a brain organization effect that occurs in straight males when they go through puberty.” He posits that “Evolution has selected for this brain organization in men that makes them attracted to the breasts in a sexual context, because the outcome is that it activates the female bonding circuit, making women feel more bonded with him. It’s a behavior that males have evolved in order to stimulate the female’s maternal bonding circuitry.”
Why might this evolutionary shift be more pronounced in humans compared to other mammals? Young suggests two key factors: monogamous relationships and face-to-face sexual behavior. Humans, unlike 97% of mammals, tend to form monogamous bonds. Furthermore, our upright posture and face-to-face mating offer greater opportunities for nipple stimulation during sex. In contrast, monogamous voles, for example, mate from behind, limiting nipple access. “So, maybe the nature of our sexuality has allowed greater access to the breasts,” Young concluded.
Young argues that alternative theories, like the notion that men prefer large breasts because they associate breast fat with better infant nourishment, are less convincing. He points out the disparity in reproductive investment between sperm and eggs, suggesting men don’t need to be as selective as this theory implies.
However, like any evolutionary explanation for complex human behaviors, Young’s theory faces scrutiny, particularly regarding cultural variations.
Anthropologist Fran Mascia-Lees from Rutgers University raises the important question of cultural differences, stating, “Always important whenever evolutionary biologists suggest a universal reason for a behavior and emotion: how about the cultural differences?”
Young counters that there’s insufficient research on breast stimulation during foreplay across diverse cultures to dismiss the nipple-oxytocin bonding loop’s significance. Interestingly, men also often enjoy nipple stimulation. A 2006 study in the Journal of Sexual Medicine found that 51.7% of undergraduate men in the UK reported nipple stimulation as arousing, compared to approximately 82% of women. Male nipples, while vestigial in terms of lactation, are still innervated and vascularized like female nipples.
However, research on nipple innervation in men and its role in male sexual arousal is limited. Perhaps, the real question isn’t solely why do men like boobs, but also why we don’t delve deeper into the erogenous nature of men’s chests as well.
