In criminal law, the age of consent is the age at which a person is considered to be capable of legally giving informed consent to sexual acts with another person. Thus somebody engaging in sex with someone below the age of consent commits a crime, called child sexual abuse. Under many jurisdictions, this is regardless of his or her own age, but in some locations, if the age difference is within a certain range, a less serious (or no) crime occurs.
The age of consent varies widely from jurisdiction to jurisdiction, though most jurisdictions in the world today have an age of consent between 14 to 18 years, but ages as young as 12 and as old as 21 also occur, with some countries in the Middle East holding female ages of consent in the single-digit range.
Increasingly the age of consent laws of a state apply not only to acts committed on its own territory, but also acts committed by its nationals and/or inhabitants on foreign territory:
In the United States the PROTECT Act (signed into law on April 30, 2003) authorizes fines and/or imprisonment for up to 30 years for U.S. citizens or residents who engage in illicit sexual conduct abroad. For the purposes of this law illicit sexual conduct includes commercial sex with anyone under 18, and all sex with anyone under 16. Previous U.S. law was less strict, only punishing those having sex either in contravention of local laws OR in commerce (i.e., prostitution); but did not prohibit non-commercial sex with, say, a 14 year-old if such sex is legal in the foreign territory.
France allows the prosecution of its own citizens on rape charges for sex with minors under 15 abroad even if it was legal with respect to the local jurisdiction. The same applies to Germany if the minor is under 14.
For inhabitants of the Netherlands it is a severe crime to have sex with a prostitute below 18, or any person below 16, anywhere in the world.
if a foreigner has had sex with a prostitute below 18, or any person below 16, anywhere in the world, even if this was legal, if this was done at a time that it was already illegal in the Netherlands, he or she becomes a criminal when immigrating to the Netherlands.
(See also Universal jurisdiction; the effective age of consent may be the highest of those corresponding to the list in Universal_jurisdiction#Applicable jurisdictions.)
Such provisions have been frequently adopted to help reduce the incidence of child sex tourism.
The enforcement practices of age of consent laws tend to vary depending on the social sensiblities of the particular culture. Often enforcement is not exercised to the letter of the law, with legal action being taken only when a sufficiently socially-unacceptable age gap exists between the two individuals, or if the perpetrator is in a position of authority over the minor (e.g. a teacher, priest or doctor). The sex of each participant also influences perceptions of an individual's guilt and therefore enforcement. Not only is enforcement more likely in the case of a larger age gap, but in the U.S. at least, laws are becoming more explicit about prohibiting sex between youngsters and authority figures, even when sex would otherwise be legal.
That the relationship was consensual is not in general a defence to having sexual relations with a person under the age of consent; however, there are some defences: common examples include a limited mistake of age defence, and a defence of similarity of age. A mistake of age defence is that the accused mistakenly believed the victim was not under the age of consent; however, where such a defence is provided, it is normally limited to apply only when the victim is above a certain age. Such a defence becomes stronger if the accused can show due diligence in determining the age of the victim.
A defence of similarity of age is that the difference in age between the accused and the victim was less than a certain number of years.
Another defence is often marriage, for those jurisdictions where the marriageable age is less than the age of consent.
18 years in dependency relationships (teacher/student etc.)
16 years if the older partner is over 18 and coerces the younger partner into sex other than by physical means, or if the older partner pays the younger partner to have sex (prostitution)
16 years if the older partner is over 21 and exploits "lack of sexual self-determination" of the younger partner (only prosecuted after complaints or "public interest", in practice rarely prosecuted with little or no punishment)
United States: varies from state to state, usually between 16 and 18; some states formerly forbade homosexual acts entirely, however such laws have been declared unconstitutional in 2003 (Lawrence v. Texas). Federal law forbids crossing state lines or international borders with the intent of having commercial sex with a person who is under 18, or any sex with a person who is under 16 and at least 4 years younger than the perpetrator (18 U.S.C. 2243, 18 U.S.C. 2423). In the US it is illegal to produce pornography featuring those under 18 and prosecutions have been commenced for cases where both partners are over the age of consent and under 18, where they were making material solely for their own consumption or that of their lawful partner. The constitutionality of these cases is uncertain.