There are 1.75 million animal species that have been noted and named by our scientific classification system. Of them, there are 5,800 types of mammal. All mammals are warm-blooded and have a four-chambered heart, but so do birds. Most mammals give birth to live young, but there are exceptions to that. Mammals all have hair, but again they share that trait with other creatures⁠—in this case spiders. In fact there is only one truly defining characteristic of mammals that is unique, and that is the trait for with they are named: the mammary gland. All mammalian species posses a gland that secretes or oozes milk for the repast of their young. In most cases the mammary gland becomes enlarged during lactation, and diminishes to almost unnoticeable when the milk is unneeded. However, amidst all 5,800 mammals, there is only one species that has perpetually swollen mammary glands. Odds are you are a member of this strangely anomalous, difficult to explain species.

At first glance the human breast defies explanation, but there are those who have spent careers and lifetimes in pursuit of explaining the relative enormity of the bust. Theories about the abundance abound. As of yet there is no consensus as to why the human female is so endowed, but staying abreast of the emerging ideas can make for titillating research.

Every variety of mammal has some sort of breast. The feature that sets the human breast apart is that in relation to the size of the body, there is no other species that retains a breast in such a swollen state. Cattle teats can be proportionately larger, but only so long as the cow is lactating; the same is true of many other species. It seems logical, seeing how lactation can be a drain of resources, that the animal’s breasts would atrophy when not in use. Some early thought on the origin of the human breast stated that because of the breast’s importance in nurturing the young, biology opted to supply extra fatty deposits to the mammary glands to help the race survive lean times of drought or meager foodstuffs. A fine idea, but it does little to explain the complex psychology surrounding the breast, and one should suppose the same phenomenon would be displayed in other species.

Therefore to handle the riddle of perpetual breasts a zoologist by the name of Desmond Morris attempted to apply gleanings from his animal research. Morris is probably best known for his 1957 art exhibition of paintings created by monkeys and his documentary series “The Human Animal”. Morris has become a somewhat controversial figure by writing papers expounding on how certain human aspects may have evolved. Among the tenets that he’s suggested is a need to exercise our inherent omnivorous heritage by eating everything, and speculation on the development of human breasts.

Morris’ hypothesis is that the breast is a purely erotic affectation⁠—a piquing notion. Most creatures in the animal kingdom tend to have the most success mating in a “male aft” sexual position because of the placement of the genitalia. In quadrupeds such as dogs and cats, all the sexual equipment is right out in plain view framed by large, rounded buttocks. Humans and their unique propensity to stand and walk erect put an end to that straight away. Changes to the pelvic region that allowed for all this walking about also causes a “face to face” mating position to have a higher effectiveness among bipeds. Morris’ contention is that it was more practical for the female to evolve an analog to the buttocks on her front than it was to re-wire the male instinct to desire an alternate sex pose. The breasts took on the roll of buttocks being the frameset of sexuality. There is an obvious cleavage of thought regarding the application of animal instincts and behaviors to humans; some maintain that humans didn’t evolve at all, and some criticize Morris as being unscientific, calling his theories untestable and claiming his methods are too abstract to apply to people.

A related, but more widely held theory is one of sexual selection. In the bygone days of early human history, the males and females were nearly indistinguishable; the male possessed small, inconspicuous genitalia much like the gorilla, and the female had no breasts of which to speak except when she was lactating or ovulating. The increase of hormones during ovulation causes a slight swelling of the breasts. From there the conclusion is obvious: not only could the male find and easily identify females of the right age, but it was at a time of her peak fertility. As males were becoming ingrained with mental coding to equate breasts with sex, the females who displayed larger breasts bred more effectively–thus the trait of extra fatty deposits in the breasts was passed to their progeny.

Like Morris’ theory, there is really no means to disprove this theory of how the breast came about, but it serves to address why females tend to carry around nicely-shaped though otherwise unnecessary blobs of fat, and at the same time address some of the psychological and social issues around the breast. Cultures around the world tend to view the breast differently, but there seems to be a widespread reluctance to letting it hang loose.

In the twenty-first century we’re still strapped to some primitive mindsets about the breast. Many cultures hold that because males do not possess these milk-extreting modified sweat glands, he can bare his chest in public forum whereas a woman cannot. It’s true that women generally have more fat in that area, allowing for a greater curved shape, however, there are men who carry fatty tissue in the same area, and display an apparent boob. Since the glands cannot be seen, what is the difference? Such is the question that the Topfree Equal Rights Association attempts to address. Their wild notion is that the female breast isn’t obscene, vulgar, dangerous, or in any way worse than man-boobs, and that if said male-mounds can be waved free in certain circumstances, then women should at the very least be allowed the same discretion without fear of legal ramifications.

Theories concerning the functional nature of the breast notwithstanding, the breast is certainly emphasized in modern culture as a sexual object. Would the free display of such enhance or detract from that image?

It seems that every few weeks there is a news story in the US concerning a nursing mother being ejected from a public place for attempting to nurse a young one, while at the same time Victoria’s Secret has made a multi-million dollar business of drawing attention to the bust. Janet Jackson’s nipple roused the wrath of armchair quarterbacks across the nation, whereas Playboy is the best selling men’s magazine in the world. The controversy around the topic is surprising considering that breasts are an ailment suffered by 52% of the population.

Since records on the subject began in the mid-1800s, the average breast size in the US has increased from a 32-B to the current average of 36-C. This may be a result of better nutrition, healthier lifestyle, or the result of the aforementioned sexual selection. If the last, however, the current popularity could be an end to natural growth; if breasts aid a female in successful mating, she no longer needs the genes to acquire the advantage, therefore the graph of breast growth may, alas, flatten.