Sex and the law deals with the regulation by law of human sexual activity. Sex laws vary from one place or jurisdiction to another, and have varied over time, and unlawful sexual acts are also called sex crimes.

Some laws regarding sexual activity are intended to protect one or all participants, while others are intended to proscribe behavior that has been defined as a crime. For example, a law may proscribe unprotected sex if one person knows that he or she has a sexual disease or to protect a minor; or it may proscribe non-consensual sex, or because of a relationship between the participants, et cetera. In general, laws may proscribe acts which are considered either sexual abuse or behavior that societies consider to be inappropriate and against the social norms. Sexual abuse is unwanted sexual contact between two or more adults or two or more minors, and, depending on laws with regard to age of consent, sexual contact between an adult and a minor.

Definitions.

Sex crimes are forms of human sexual behavior that are considered sufficiently unacceptable and harmful to society to be regarded as criminal. Someone who commits one is said to be a sex offender. Some sex crimes are crimes of violence that involve sex. Others are violations of social taboos, such as incest, sodomy, indecent exposure or exhibitionism. There is much variation among cultures as to what is considered a crime or not, and in what ways or to what extent crimes are punished.

Western countries are often far more tolerant of acts, such as oral sex, that have traditionally been held to be crimes in some countries, but combine this with lesser tolerance for the remaining crimes. By contrast, many cultures with a strong religious tradition consider a far broader range of activities to be serious crimes.

As a general rule, the law in many countries often intervenes in sexual activity involving young or adolescent children below the legal age of consent, non-consensual deliberate displays or illicit watching of sexual activity, sex with close relatives (incest), harm to animals, acts involving the deceased (necrophilia), and also when there is harassment, nuisance, fear, injury, or assault of a sexual nature, or serious risk of abuse of certain professional relationships. Separately, the law usually regulates or controls the censorship of pornographic or obscene material as well. A rape charge can only be issued when a persons of any age does not provide consent for sexual activity.