Dear Straight Dope:
Is it illegal to answer my door naked? What about if people can see me from the street? Can I be naked in my front yard as long as I stay on my property?
SDSTAFF Gfactor replies:
It depends on the jurisdiction you live in, Chris, but very generally speaking, yes, yes, and no. Being on your property has little to do with it. The crime you're talking about is usually called indecent exposure and relies on the idea of public nudity – public in this sense meaning only that you expose yourself where others might see you. Folks have been charged with indecent exposure for exhibiting themselves to unwilling observers inside a private residence, or for being naked inside a house when they could be seen through a window.
At common law it wasn't even necessary that anyone actually see you, and some statutes are written that way too. For example, in State v. Martin (Iowa 1904) a man was indicted for indecent exposure for what was presumably an assignation with his girlfriend "on a public highway." The indictment charged that he had exposed himself in her presence (as so often happens during sex) but didn't claim that she saw him do so. The appeal was based on a challenge to the indictment, which gave his lawyers some leeway to speculate: "[T]he indictment does not charge that any one saw the indecent exhibition, or that it was made with the intent that any one should see it, or that the exposure was made under circumstances when it was possible that any one should see it, or that it was in public, or without the consent of the woman named. It is also said that the allegations may be literally true, and yet the appellant and the woman may have been miles apart, and may have been ignorant of one another's presence upon the public road; that defendant may have been entirely alone, or the alleged exhibition may have been in the darkness of night and without evil intent." That's what they all say, isn't it? The court didn't buy the argument. Instead it held that "the crime as defined by the statute does not require that the exposure shall be made in the actual sight of any person," and quoted a previous case where it had concluded that "if a case should be made by confession, corroborated by circumstances, a defendant might properly be convicted of this offense, although no person witnessed the indecent act."
So in some places you could be convicted for being naked where others might have seen you even if nobody did. Other states explicitly require witnesses, and some require the witnesses to be of the opposite sex.
Of course, plain old public nudity isn't illegal everywhere. Vermont has no state law against it, leaving it up to individual municipalities. And there are always unique statutory interpretations. For example, in Maine, the law prohibits exposure of genitalia. Men who appear in public naked are routinely convicted of indecent exposure, while women are often acquitted because their genitalia is not usually visible, even if they aren't wearing clothes. Another jurisdiction has held that the display of pubic hair doesn't violate its public nudity laws. Some states require that the exposure be with lewd intent; still others require that the exposure be "likely to cause affront or alarm." At the other extreme, some towns have simply passed ordinances that basically ban all public nudity. In some cases, mothers have been charged with public-nudity offenses for nursing their children in view of others, although most jurisdictions have adopted laws to exempt nursing from such charges.
An issue that wasn't present when more states recognized common-law offenses is whether one can be required to register as a sex offender following an indecent exposure conviction. According to a 2007 publication [pdf] by Human Rights Watch, "[a]t least 13 states require registration for public urination; of those, two limit registration to those who committed the act in view of a minor . . . . At least 32 states require registration for exposing genitals in public[.] Of those, seven states require the victim to be a minor."
Another recent issue involving public nudity or near nudity is the recent spate of laws dealing with sagging pants, as I mentioned in my staff report on weird laws. While many jurisdictions have attempted to curtail sagging pants with special ordinances, others have threatened to arrest those with sagging pants under existing indecent exposure laws, although not without drawing protest.