From The Art and Popular Culture Encyclopedia
Indecent exposure is the deliberate exposure by a person of a portion or portions of his or her own body under circumstances where such an exposure is likely to be deemed an offense against prevalent standards of decency and may in fact be a violation of law.
In most public places other than designated areas where nudity is acceptable such as in nude beaches, unwelcome exposure of an adult's genitalia is the most common example of indecent exposure. More specific cases of indecent exposure may also involve masturbation, sexual intercourse, etc. in a public place.
During the Victorian era, exposure of a woman's legs was considered indecent in much of the Western world. As late as the 1930s, both women and men were largely prevented from bathing or swimming in public places without wearing bathing suits that covered above the waist. An adult woman exposing her navel was also considered indecent in the West up through as late as the 1960s and 1970s. Today, however, it is not uncommon for women to go topfree at public beaches throughout Europe, South America, Australia and New Zealand. Meanwhile, many other types of societies worldwide currently enforce strict standards of bodily modesty, an example of which is the Burqa formerly imposed upon women by the Taliban regime of Afghanistan. In Pakistan, exposure of any part of an adult woman's body is considered indecent except for arms up to elbows, feet and head including neck; however, wearing half sleeves and keeping the head uncovered are considered liberal and modern rather than the norm.
What qualifies as indecent exposure varies with the authority having jurisdiction. Indecent exposure is often prohibited as a criminal offense. For example, before the Labour Party of the United Kingdom revised the law, "indecent exposure" was defined exclusively as a man exposing his erect penis to the public.
Although the phenomenon widely known as flashing may be free from sexual motive or intent, it nonetheless requires the public exposure of the genitals and/or female breast or vagina and is therefore defined by statute in many states of the United States as prohibited criminal behavior.
Breastfeeding does not constitute indecent exposure under the laws of the United States, Canada, or Scotland. In the United States, the federal government and the majority of states have enacted laws specifically protecting nursing mothers from harassment by others. Legislation ranges from simply exempting breastfeeding from laws regarding indecent exposure, to outright full protection of the right to nurse. However, mainstream ambivalence towards breastfeeding may prevent many women from exercising this right. Laws protecting the right to nurse aim to change attitudes and promote increased feelings of freedom and entitlement to breastfeed in public.
Legal Status in the United States
In the fifty states of the United States indecent exposure is defined by state law as exposure of the genitals and/or the female breast in a public place and may in some states require evidence of intent to shock, arouse or offend other persons. The act is prohibited by state laws titled variously as Indecent Exposure, Sexual Misconduct, Public Lewdness, and Public Indecency. It is a criminal offense in all fifty states and is punishable by fines and/or imprisonment, and in some states a conviction results in having to register as a sex offender.
Indecent exposure is also defined as a crime by the U.S. Uniform Code of Military Justice Sec. 552. regarding rape, sexual assault, and other sexual misconduct.
Exemption for breastfeeding of infants
A majority of states have enacted statutes specifically permitting the exposure of the female breast by women breast-feeding infants, or exempting such women from prosecution under applicable statutes. 
U.S. Public Law 106-58 Sec. 647. enacted in 1999, specifically provides that "a woman may breastfeed her child at any location in a Federal building or on Federal property, if the woman and her child are otherwise authorized to be present at the location."
Legal Status in Australia
- Social nudity
- Sex crime