The age of consent is the age at which a person is considered to be legally competent to consent to sexual acts. Consequently, an adult who engages in sexual activity with a person younger than the age of consent cannot claim that the sexual activity was consensual, and such sexual activity may be considered child sexual abuse or statutory rape. The person below the minimum age is regarded as the victim and their sex partner is regarded as the offender, unless both are underage. The purpose of setting an age of consent is to protect an underage person from sexual advances.

The term age of consent rarely appears in legal statutes.^[1] Generally, a law will instead establish the age below which it is illegal to engage in sexual activity with that person. It has sometimes been used with other meanings, such as the age at which a person becomes competent to consent to marriage,^[2] but the meaning given above is the one now generally understood. It should not be confused with other laws regarding age minimums including, but not limited to, the age of majority, age of criminal responsibility, voting age, drinking age, and driving age.

Age of consent laws vary widely from jurisdiction to jurisdiction,^[1] though most jurisdictions set the age of consent in the range 14 to 18. The laws may also vary by the type of sexual act, the gender of the participants or other considerations, such as involving a position of trust; some jurisdictions may also make allowances for minors engaged in sexual acts with each other, rather than a single age. Charges and penalties resulting from a breach of these laws may range from a misdemeanor, such as corruption of a minor, to what is popularly called statutory rape.

There are many "grey areas" in this area of law, some regarding unspecific and untried legislation, others brought about by debates regarding changing societal attitudes, and others due to conflicts between federal and state laws. These factors all make age of consent an often confusing subject, and a topic of highly charged debates.^[1]

In traditional societies, the age of consent for a sexual union was a matter for the family to decide, or a tribal custom. In most cases, this coincided with signs of puberty, menstruation for a woman, and pubic hair for a man.^[3] The ancient Greek poet Hesiod in Works and Days (c. 700 BC) suggests that a man should marry around the age of thirty, and that he should take a wife who is five years past puberty.

Reliable data for ages at marriage is scarce. In England, for example, the only reliable data in the early modern period comes from property records made after death. Not only were the records relatively rare, but not all bothered to record the participants' ages, and it seems that the more complete the records are, the more likely they are to reveal young marriages. Modern historians have sometimes shown reluctance to accept evidence of young ages of marriage, dismissing it as a 'misreading' by a later copier of the records.^[3]

In the 12th century, Gratian, the influential founder of canon law in medieval Europe, accepted the age of puberty for marriage to be around twelve for girls and around fourteen for boys but acknowledged consent to be meaningful if both children were older than seven years of age.^[4] There were authorities that said that consent could take place earlier. Marriage would then be valid as long as neither of the two parties annulled the marital agreement before reaching puberty, or if they had already consummated the marriage. Judges sometimes honored marriages based on mutual consent at ages younger than seven: in contrast to established canon, there are recorded marriages of two- and three-year-olds.^[3]

The first recorded age-of-consent law dates from 1275 in England; as part of its provisions on rape, the Statute of Westminster 1275 made it a misdemeanor to "ravish" a "maiden within age," whether with or without her consent. The phrase "within age" was later interpreted by jurist Sir Edward Coke (England, 17th century) as meaning the age of marriage, which at the time was twelve years of age.^[5]

The American colonies followed the English tradition, and the law was more of a guide. For example, Mary Hathaway (Virginia, 1689) was only nine when she was married to William Williams.^[6] Sir Edward Coke "made it clear that the marriage of girls under 12 was normal, and the age at which a girl who was a wife was eligible for a dower from her husband's estate was 9 even though her husband be only four years old."^[3]

In the 16th century, a small number of Italian and German states set the minimum age for sexual intercourse for girls, setting it at twelve years. Towards the end of the 18th century, other European countries also began to enact similar laws. The first French Constitution of 1791 established the minimum age at eleven years. Portugal, Spain, Denmark and the Swiss cantons initially set the minimum age at ten to twelve years.^[7]

Age of consent laws were, historically, difficult to follow and enforce: legal norms based on age were not, in general, common until the 19th century, because clear proof of exact age and precise date of birth were often unavailable.^[7]

In Christian societies, sex outside marriage was forbidden. Older children were themselves often punished for being complicit in sexual interaction with an adult. Western Christianity also deemed that children were born into the original sin, and, as such, were perceived as inherently immoral.^[8] Children had very few rights and were considered the chattel of the father.^[8] From the late 18th century, and especially in the 19th century, attitudes started to change. By the mid-19th century there was increased concern over child sexual abuse.^[8]

A general shift in social and legal attitudes toward issues of sex occurred during the modern era. Attitudes on the appropriate age of permission for females to engage in sexual activity drifted toward adulthood. While ages from ten to thirteen years were typically regarded as acceptable ages for sexual consent in Western countries during the mid-19th century,^[1] by the end of the 19th century changing attitudes towards sexuality and childhood resulted in the raising of the age of consent.^[5]

English common law had traditionally set the age of consent within the range of ten to twelve years old, but the Offences Against the Person Act 1875 raised this to thirteen in Great Britain and Ireland. Early feminists of the Social Purity movement, such as Josephine Butler and others, instrumental in securing the repeal of the Contagious Diseases Acts, began to turn towards the problem of child prostitution by the end of the 1870s. Sensational media revelations about the scourge of child prostitution in London in the 1880s then caused outrage among the respectable middle-classes, leading to pressure for the age of consent to be raised again.

The investigative journalist William Thomas Stead of the Pall Mall Gazette was pivotal in exposing the problem of child prostitution in the London underworld through a publicity stunt. In 1885 he "purchased" one victim, Eliza Armstrong, the thirteen-year-old daughter of a chimney sweep, for five pounds and took her to a brothel where she was drugged. He then published a series of four exposés entitled The Maiden Tribute of Modern Babylon, which shocked its readers with tales of child prostitution and the abduction, procurement, and sale of young English virgins to Continental "pleasure palaces". The "Maiden Tribute" was an instant sensation with the reading public, and Victorian society was thrown into an uproar about prostitution. Fearing riots on a national scale, the Home Secretary, Sir William Harcourt, pleaded in vain with Stead to cease publication of the articles. A wide variety of reform groups held protest meetings and marched together to Hyde Park demanding that the age of consent be raised. The government was forced to propose the Criminal Law Amendment Act 1885, which raised the age of consent from thirteen to sixteen and clamped down on prostitution.^[9]

In the United States, as late as the 1880s most states set the minimum age at ten to twelve (in Delaware, it was seven in 1895).^[10] Inspired by the "Maiden Tribute" articles, female reformers in the U.S. initiated their own campaign,^[11] which petitioned legislators to raise the legal minimum age to at least sixteen, with the ultimate goal to raise the age to eighteen. The campaign was successful, with almost all states raising the minimum age to sixteen to eighteen years by 1920.^[5][12]

In France, Portugal, Denmark, the Swiss cantons and other countries, the minimum age was raised to between thirteen and sixteen years in the following decades.^[5] Though the original arguments for raising the age of consent were based on morality, since then the raison d'être of the laws has changed to child welfare and a so-called right to childhood or innocence.^[13]

In France, under the Napoleonic Code, the age of consent was set in 1832 at eleven,^[14] and was raised to thirteen in 1863.^[15] It was increased to fifteen in 1945.^[16]

In Spain, it was set in 1822 at "puberty age", and changed to twelve in 1870,^[17] which was kept until 1999, when it became 13;^[18][19] and in 2015 it was raised to 16.^[20][21][22]

In the 21st century, concerns about child sex tourism and commercial sexual exploitation of children gained international prominence, and have resulted in legislative changes in several jurisdictions, as well as in the adoption of several international instruments.

The Council of Europe Convention on the Protection of Children against Sexual Exploitation and Sexual Abuse (Lanzarote, 25 October 2007), and the European Union's Directive 2011/92/EU of the European Parliament and of the Council of 13 December 2011 on combating the sexual abuse and sexual exploitation of children and child pornography^[23] were adopted.

The Optional Protocol on the Sale of Children, Child Prostitution and Child Pornography came into force in 2002.

The Protocol to Prevent, Suppress and Punish Trafficking in Persons, especially Women and Children, which came into force in 2003, prohibits commercial sexual exploitation of children.^[24]

The Council of Europe Convention on Action against Trafficking in Human Beings (which came into force in 2008) also deals with commercial sexual exploitation of children.

Several Western countries have raised their ages of consent recently. These include Canada (in 2008—from 14 to 16); and in Europe, Iceland (in 2007—from 14 to 15), Lithuania (in 2010—from 14 to 16), Croatia (in 2013—from 14 to 15), and Spain (in 2015—from 13 to 16).

The International Criminal Court Statute does not provide a specific age of consent in its rape/sexual violence statute, but makes reference to sexual acts committed against persons "incapable of giving genuine consent"; and the explicative footnote states, "It is understood that a person may be incapable of giving genuine consent if affected by natural, induced or age-related incapacity." (see note 51)^[25]

Sexual relations with a person under the age of consent is a crime in most countries; exceptions to this include Yemen, and Saudi Arabia. Jurisdictions use a variety of terms for the offense, including child sexual abuse, statutory rape, illegal carnal knowledge, corruption of a minor,^[1] besides others.

The enforcement practices of age-of-consent laws vary depending on the social sensibilities of the particular culture (see above). 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 power over the minor (e.g. a teacher, minister, or doctor). The sex of each participant can also influence perceptions of an individual's guilt and therefore enforcement.^[1]

The threshold age for engaging in sexual activity varies between jurisdictions. Most jurisdictions have set a fixed age of consent.^[26] However, some jurisdictions permit sex with a person after the onset of their puberty, such as Yemen, but only in marriage. Ages can also vary based on the type of calendar used, such as the Lunar calendar,^[27] how birth dates in leap years are handled, or even the method by which birth date is calculated.^[28]

The age of consent is a legal barrier to the minor's ability to consent and therefore obtaining consent is not in general a defense to having sexual relations with a person under the prescribed age, for example:

A growing number of countries have specific extraterritorial legislation that prosecutes their citizens in their homeland should they engage in illicit sexual conduct in a foreign country with children. In 2008, ECPAT reported that 44 countries had extraterritorial child sex legislation.^[41] For example, PROTECT Act of 2003, a federal United States law bans sexual activity by its citizens with foreigners or with U.S. citizens from another state, if the partner is under 18 and the activity is illegal under the federal, state, or local law. This applies in cases where any of the partners travels into or out of the United States, or from one state into another, for the purpose of an illegal sexual encounter.^[42][43]

There is debate as to whether the gender of those involved should lead to different treatment of the sexual encounter, in law or in practice. Traditionally, age of consent laws regarding vaginal intercourse were often meant to protect the chastity of unmarried girls.^[7] Many feminists and social campaigners in the 1970s have objected to the social importance of virginity, and have also attempted to change the stereotypes of female passivity and male aggression; demanding that the law protect children from exploitation regardless of their gender, rather than dealing with concerns of chastity. This has led to gender-neutral laws in many jurisdictions.^[7] On the other hand, there is an opposing view which argues that the act of vaginal intercourse is an "unequal act" for males and females, due to issues such as pregnancy, increased risk of STDs,^[44] and risk of physical injury if the girl is too young and not physically ready. In the US, in Michael M. v. Superior Ct.450 U.S. 464 (1981) it was ruled that the double standard of offering more legal protection to girls is valid because "the Equal Protection Clause does not mean that the physiological differences between men and women must be disregarded".^[45]

Traditionally, many age of consent laws dealt primarily with men engaging in sexual acts with underage girls and boys (the latter acts often falling under sodomy and buggery laws). This means that in some legal systems, issues of women having sexual contact with underage partners were rarely acknowledged. For example, until 2000, in the UK, before the Sexual Offences (Amendment) Act 2000, there was no statutory age of consent for lesbian sex.^[46] In New Zealand, before 2005, there were no age of consent laws dealing with women having sex with underage boys.^[47] Previously, in Fiji, male offenders of child sexual abuse could receive up to life imprisonment, whilst female offenders would receive up to seven years.^[48] Situations like these have been attributed to societal views on traditional gender roles, and to constructs of male sexuality and female sexuality; according to E Martellozzo, "[V]iewing females as perpetrators of sexual abuse goes against every stereotype that society has of women: women as mothers and caregivers and not as people who abuse and harm".^[49] Alissa Nutting argues that women are not acknowledged as perpetrators of sex crimes because society does not accept that women have an autonomous sexuality of their own.^[50]

The age at which a person can be legally married can differ from the age of consent. In jurisdictions where the marriageable age is lower than the age of consent, those laws usually override the age of consent laws in the case of a married couple where one or both partners are below the age of consent. Some jurisdictions prohibit all sex outside of marriage irrespective of age, as in the case of Yemen.^[51][52]

In many countries, there are specific laws dealing with child prostitution.

In some countries, states, or other jurisdictions, the age of consent may be lower than the age at which a person can appear in pornographic images and films. In many jurisdictions, the minimum age for participation and even viewing such material is 18. As such, in some jurisdictions, films and images showing individuals under the age of 18, but above the age of consent, that meet the legal definition of child pornography are prohibited despite the fact that the sexual acts depicted are legal to engage in otherwise under that jurisdiction's age of consent laws. In those cases, it is only the filming of the sex act that is the crime as the act itself would not be considered a sex crime. For example, in the United States under federal law it is a crime to film minors below 18 in sexual acts, even in states where the age of consent is below 18.^[43] In those states, charges such as child pornography can be used to prosecute someone having sex with a minor, who could not otherwise be prosecuted for statutory rape, provided they filmed or photographed the act.^[53]

Jailbait images can be differentiated from child pornography, as they do not feature minors before the onset of puberty, nor do they contain nudity.^[54][55] The images are, however, usually sexualized,^[54] often featuring tween or young teenagers in bikinis, skirts,^[56] underwear or lingerie.^[57] Whether or not these images are legal is debated. When questioned regarding their legality legal analyst Jeffrey Toobin stated he thought it was not illegal, though legal expert Sunny Hostin was more skeptical, describing jailbait images as "borderline" child pornography which may be illegal.^[58][59]

The human immune system continues to develop after puberty.^[60] The age of exposure has an influence upon if the immune system can fend off infections in general, and this is also true in the case of some sexually transmitted diseases. For example, a risk factor for HPV strains causing genital warts is sexual debut at a young age;^[61] if this extends to the cancer causing strains, then sexual debut at a young age would potentially also increase risk of persistence of HPV infections that cause the very HPV induced cancers that are being diagnosed in spiking numbers of relatively young people.^[61]

Age-of-consent reform refers to the efforts of some individuals or groups, for different reasons, to alter or abolish age-of-consent laws. These efforts advocate positions such as: