As a paraphilia, breast fetishism (also known as mastofact, breast partialism, or mazophilia) is a highly atypical sexual interest focused on female breasts (see partialism). The term breast fetishism is also used in the non-paraphilic sense, to refer to cultural attention to female breasts and the sexuality they represent, with debate existing as to whether the modern widespread fascination with breasts among heterosexual males in western societies is a sexual fetish.
Scientists have hypothesized that non-paraphilic sexual attraction to breasts is the result of their function as a secondary sex characteristic. For instance, zoologist and ethologist Desmond Morris theorizes that cleavage is a sexual signal that imitates the image of the cleft between the buttocks, which according to Morris in The Naked Ape is also unique to humans, other primates as a rule having much flatter buttocks. Evolutionary psychologists theorize that humans' permanently enlarged breasts, in contrast to other primates' breasts, which only enlarge during ovulation, allows human females to "solicit [human] male attention and investment even when they are not really fertile".
The reverence and theorizing shown to breasts also appears in the science of modern civilization. Breast fetishism is claimed to be an example of a contagious thought (or meme) spreading throughout society, and that breasts are features that have evolved to influence human sexuality rather than serve an exclusive maternal function.
In clinical literature of the 19th century, the sexual focus on breasts was considered a form of paraphillia, but, in modern times, this attraction is considered normal unless it is highly atypical and is therefore a form of partialism.
The term breast fetishism is also used within ethnographic and feminist contexts to describe a society with a culture devoted to breasts, usually as sexual objects. Some feminists have argued that incidences of breast fetishism have been found going back to the neolithic era, with the goddess shrines of Catal Huyuk (in modern Turkey). The archaeological excavations of the town in c. 1960 revealed the walls of the shrine(s) adorned with disembodied pairs of breasts that appeared to have "an existence of their own". Elizabeth Gould Davis argues that breasts (along with phalluses) were revered by the women of Catal Huyuk as instruments of motherhood, but it was after what she describes as a patriarchal revolution – when men had appropriated both phallus worship and "the breast fetish" for themselves – that these organs "acquired the erotic significance with which they are now endowed".
Some authors from the United States have made the statement that attraction to the female breast is a sexual fetish, that it is the American fetish-object of choice, and that breast fetishism is predominantly found in the United States.
There is a widespread fascination with women's breasts, and especially their size. Modern female fashions which focus on tight clothing and the display of cleavage have been attributed to the increase in breast fetishism. Many people in Western culture, both male and female, consider breasts an important female secondary sex characteristic, an important aspect of femininity, and many women use décolletage or a low neckline that exposes cleavage as part of their physical and sexual attractiveness.
Display of cleavage with a low neckline is often regarded as a form of feminine flirting or seduction, as well as aesthetic or erotic. Most men derive erotic pleasure from seeing a woman's breasts, and some people derive pleasure in their female partner exposing cleavage. When cleavage is enhanced with a push-up bra or exposed by a low neckline it may draw attention. During adolescence, some girls become obsessed with body image including breast size and shape. In South Africa, Wonderbra sponsors a National Cleavage Day during which women are encouraged to display their cleavage.
In Western and some other societies, there are differences of opinion as to how much cleavage exposure is acceptable in public. In contemporary Western society, the extent to which a woman may expose her breasts depends on social and cultural context. Displaying cleavage or any part of female breast may be considered inappropriate or even prohibited by dress codes in some settings, such as workplaces, churches, and schools, while in some spaces showing as much cleavage as possible can be permissible or even encouraged. The exposure of nipples or areolae is almost always considered toplessness, considered by some to be immodest and in some instances as lewd or indecent behavior. Art historian James Laver argued that the changing standards of revealing cleavage is more prominent in evening wear than in day wear in the Western world.
Film producers such as Russ Meyer produced films which featured actresses with large breasts. Lorna (1964) was the first of his films where the main female part was selected on the basis of breast size. Other large breasted actresses used by Meyer include Kitten Natividad, Erica Gavin, Lorna Maitland, Tura Satana, and Uschi Digard among many others. The majority of them were naturally large breasted and he occasionally cast women in their first trimesters of pregnancy to enhance their breast size even further. Author and director William Rotsler said: "with Lorna Meyer established the formula that made him rich and famous, the formula of people filmed at top hate, top lust, top heavy." The practice of breast augmentation has become more common.