Laws regarding incest are sometimes expressed in terms of degrees of relationship. The consanguinity (but not affinity) relationships may be summarized as follows:
The degree of relationships is calculated by counting the number of generations back to a common ancestor. Most laws regarding prohibited degree of kinship concern relations of r = 25% or higher, while most permit unions of individuals with r = 12.5% or lower. In some US states, cousin marriages are prohibited. Also, most laws make no provision for the rare case of marriage between double first cousins. Incest laws may also include prohibitions of unions between biologically unrelated individuals if there is a close legal relationship, such as adoption.
Consensual incest between adults is legal in Côte d'Ivoire (Ivory Coast).
In South Africa, since 2007, incest is the sexual penetration between persons who are related as follows:lineally, that is, if one person is a direct descendant of the other.
within the first degree of consanguinuity, that is, where one person is a direct descendant of a parent of the other; this category includes siblings as well as an uncle or aunt with a niece or nephew.
within the first degree of affinity, that is, where one person is the direct ancestor or descendant of the spouse of the other person.
as adoptive parent and adopted child.
Before 2007, incest was a common law offence which extended to the same degrees of relationship but which applied only to vaginal intercourse.
In Zimbabwe, all forms of incest could result in a jail sentence, including cousins as far as fourth cousins.
Barring the Special Administrative Regions of Hong Kong and Macau, which have separate legal codes, consensual incest between adults is legal in the People's Republic of China.
In Hong Kong, it is illegal to have sexual intercourse with certain close relatives, even if they are consenting adults. The prohibited relationships are grandfather-granddaughter, father-daughter, brother-sister and mother-son. Punishment is up to 20 years' imprisonment for male offenders and up to 14 years' imprisonment for female offenders. The law does not cover sexual intercourse with more distant relatives, such as an aunt, uncle, niece, nephew and cousin. It only addresses male-on-female and female-on-male sexual intercourse, and it appears that consensual same-sex incest is not illegal. The law makes an assumption that a female below the age of 16 has no ability to consent to sexual intercourse, therefore a female below 16 cannot commit incest.
According to Macau's civil code, people in direct line kinship or in the second degree of collateral kinship cannot marry each other.
According to the Article 82 of Iran's Penal code, incest is forbidden and its punishment is up to death penalty.
The Indian Penal Code (IPC) does not contain any specific provision against incest, but there are general provisions relating to sexual abuse of children by their custodian, such as a parent or teacher. More over the rule of kinship or marriage is governed by the different marriage laws.
In Malaysia, it is incest to have sexual intercourse with a person who under the law, religion, custom or usage that applies to the person he or she is not permitted to marry on account of their relationship.
In addition to whipping, persons convicted of incest face a minimum sentence of 6 years' imprisonment and a maximum sentence of 20 years' imprisonment. It is a defense against the charge if the person did not know the relationship was not permitted or if the sexual intercourse was done without his or her consent. Girls below the age of 16 and boys below the age of 13 are deemed to be incapable of giving consent. (The age of consent for sex in Malaysia is 16 for both sexes.)
While it is unclear to which family members the incest law applies, a verdict from the High Court in Sabah and Sarawak in 2011 provided some indication about the sentencing guidelines. It described incest as a "heinous crime" but that the degree of kinship between the parties dictates the "level of repulsion" which the court translates into a sentence imposed. The verdict said the worst on such a scale is incest committed by a father to his biological daughter or a brother to his biological sister, and that such offenders should receive the harshest sentence. It said an uncle and his maternal niece committing incest is not on that same level and, if there was no violence involved, the length of the sentence should reflect it.
There are more severe sentences for those who commit incest through rape. The offence of incestuous rape is punishable with not less than 8 years' imprisonment and not more than 30 years' imprisonment. In addition, those convicted receive not less than 10 strokes.
Malaysian law also considers sexual intercourse with the stepfamily to be incestuous.
The legal code of Pakistan defines incest as marriage (consortion) between a male and either his:wife or former wife of father, grandfather and further ancestors
Mother, grandmother and further ancestors
Daughter, granddaughter and further descendents
full or half sister
parents' sisters, grandparents' sisters and further ancestors' sisters
daughter, granddaughter and further descendent of full or half sibling
Mother, grandmother and further ancestors of wife or former wife
Daughter, granddaughter of wife or former wife
Wife or former wife of true son or grandson and further descendents
Both participants are guilty if they commit the above acts and are charged with Zina.
The Philippine Family Code specifies that marriages between collateral blood relatives whether legitimate or illegitimate, up to the fourth civil degree shall be void from the beginning.
Section 376G of the Penal Code specifies that "a male, of or above the age of 16, having sexual relations with his grand-daughter, daughter, sister, half-sister, mother or grandmother, with or without consent, shall be guilty of an offence. Any woman of or above the age of 16 years who, with consent, permits her grandfather, father, brother, half-brother, son or grandson (whether such relationship is or is not traced through lawful wedlock) to penetrate her in the manner described in subsection (1)(a) or (b), knowing him to be her grandfather, father, brother, half-brother, son or grandson, as the case may be, shall be guilty of an offence."
In Taiwan, officially the Republic of China (ROC), Article 983 of the Civil Code prohibits marrying any lineal relative by blood or by marriage, collateral relative by blood if is within the sixth degree of relationship (except relative by adoption who is of the same rank), or if collateral relative by marriage is within the fifth degree of relationship of a different rank. Relatives by marriage or adoption are prohibited marriage and cannot marry even after the marriage or adoption has ended. The degree of relationship is calculated vertically, therefore a sibling is within the second degree of relationship. The Judicial Yuan Interpretation No.32 and No.91 allows marriage between siblings by adoption when the adoption was intended for the marriage. When the interpretation was made, it was not uncommon for parents to adopt a child so that their own child can marry the adopted child when both children have grown up. Article 230 of the Penal Code prohibits sexual intercourse between any lineal relatives by blood or collateral relatives within the third degree of relationship by blood. Violators may be imprisoned for up to 5 years.
Incestuous relations between adults (over 18 years old) is not prohibited by law. Incestuous marriage is prohibited by law.
Incest between people of direct blood line is illegal in Vietnam and may result in six months to five years of imprisonment.
Most European countries prohibit incest; apart from those listed below, these include: (all articles refer to the Penal Codes) Albania Article 106, Ukraine Article 155 Paragraph 2, Slovenia Article 195, Slovakia Section 203, Serbia Article 197 (refers only between an adult and under-aged), Poland Article 201, Norway Article 197 and 198, Bosnia and Herzegovina Article 201, Hungary Article 199, Bulgaria, Croatia Article 198, and Cyprus Article 147.
Countries which allow incest between consenting adult siblings include France, Spain, the Benelux and Portugal.
In Austria, incest between lineal ancestors and descendants and between full siblings is prohibited. It is punishable by up to two years in prison.
In Denmark, incest is sex between lineal ancestors and descendants and between full siblings. Sex with a descendant is punishable by up to 6 years' imprisonment. Sex between siblings is punishable by up to 2 years' imprisonment.
In Finland, sexual acts between one's full sibling (but not half-sibling), ancestor or descendant is punishable from a fine up to 2 years in prison for "sexual act between close relative". But it will not be punished if the person in question has been under 18 years old when have performed the sexual act with parent or grandparent or the person have been forced or illegally persuaded to perform the sexual act. The marriage law defines, that marriage between one's sibling, half-sibling, ancestor or descendant is forbidden.
The 1810 penal code promulgated by Napoleon I and adopted throughout most of Europe abolished incest laws in France, Belgium and Luxembourg. On 27 January 2010, France reinstated laws against incest. The new law, however, defines incest as rape or sexual abuse on a minor "by a relative or any other person having lawful or de facto authority over the victim". Incest between consenting adults is not prohibited.
In Germany, incest is legally defined as vaginal intercourse between lineal ancestors and descendants (parents, grandparents, great-grandparents and their children, grandchildren, great-grandchildren) and between full and half siblings. The penalty is a fine or up to 3 years of prison. Incest between relatives who are minors (below 18 years old) at the time of offence is not punishable but remains a crime, therefore aiding and abetting of incest between related minors is punishable.
Regarding marriage, the same rules apply and prohibit marriage between aforementioned relatives.
The criminal liability of incest among consenting adults is disputed in Germany. In the case of Patrick Stübing, the Federal Constitutional Court ruled in 2008 that the criminalization of incest is constitutional in a 7:1 vote with one judge dissenting.
In September 2014 the German Ethics Council recommended that the government abolish laws criminalizing consensual incest between adult siblings, arguing that such bans impinge upon citizens.
Article 345 of the Greek Penal Code as modified by Article 2, Paragraph 8 of Law 3625/2007 and Article 3 Paragraph 10 of Law 3727/2008 prohibits incestuous relations between relatives of both ascending and descending line, and between half or full siblings, and imposes (1) for the ascending relative (for example father, uncle, grandfather etc.): at least 10 years' imprisonment if the descending relative is under 15 years old, imprisonment if 15 but not 18 years old, and maximum 2 years' imprisonment if 18 years and older; (2) for the descending relative (for example child, nephew etc.) maximum 2 years' imprisonment; (3) for half or full siblings maximum 2 years' imprisonment. Paragraph 2 of Article 345 Penal Code also states that if the descending relative and the half or full siblings were under 18 years old, they might be cleared of any charge.
Also, Article 1357 of the Greek Civil Code prohibits the marriage of relatives of direct blood line in totality, and up the four degrees of consanguinity of the secondary blood line (for example you can marry the first cousin of your mother / father, but not your first cousin). Article 1358 of the Greek Civil Code also prohibits the marriage of relatives in law totally in direct blood line, and up the third degree of the secondary blood line.
Incest is illegal in the Republic of Ireland under the Punishment of Incest Act 1908, which pre-dates the foundation of the state.
It is illegal for a male to have sexual intercourse with his granddaughter, mother, daughter or sister (including half-sister); and for a female (over sixteen years of age) with her grandfather, father, son or brother (including half-brother). The act does not refer to other familial relationships (such as grandson-grandmother), or same-sex relations.
It is punishable by up to seven years' imprisonment for a female and up to life imprisonment for a male. The maximum sentence for males was increased from seven years to twenty years by the Criminal Justice Act, 1993; and further increased to life imprisonment by the Criminal Law (Incest Proceedings) Act, 1995.
The maximum sentence for females has never been increased from the seven years specified in the original 1908 act. A private members' bill introduced in 2012 by Denis Naughten TD attempted to redress this inequality in sentencing by increasing the maximum sentence for females to life imprisonment. However, during a speech made during the second stage reading of the bill in March 2014, Justice Minister Alan Shatter TD stated that while he was not opposed to the bill in principle, a sexual offences bill announced by the government on 17 December 2013 will "include measures to equalise upwards the penalties for incest by male and female offenders" and also "take a more comprehensive approach to reform of the law in this area".
Occasionally, offenders convicted of incest will be admitted to a psychiatric hospital for psychiatric treatment.
Incest is illegal in Italy only if it provokes public scandal, according to Article 564 of the Penal code and punishable from 2 to 8 years' imprisonment, open to more years for the older person if the other was under aged.
Consensual incest between adults is legal in the Netherlands. Marriage is forbidden between ancestors and descendents or between siblings, although the Minister of Justice may grant dispensation in the case of siblings by adoption. Marriage is also forbidden between blood relations of the third and forth degree, unless both partners have signed a declaration of consent. (Dutch civil law book 1, articles 41 and 42.)
In Poland, incest is defined in Article 201 of the Penal Code as sexual intercourse with an ancestor, descendant, guardian, ward, brother, or sister, and is punishable by imprisonment for no less than 3 months and no more than 5 years.
Incest is not specifically prohibited under Portuguese law.
Incest is defined in the Penal Code as "consensual sexual relations between lineal relatives or between siblings" and is punished by 1 to 5 years in prison.
In Russia, consensual sex between adults, including incest, is not a crime. However, under the Family Code of Russia, persons who are related lineally, siblings, half-siblings, and a stepparent and a stepchild may not marry.
Consensual incest between adults is legal in Spain.
Incest with a descendant or a full sibling is prohibited by law in Sweden. Half-siblings can marry, but require special approval by the government.
Article 213 of the Swiss Penal Code prohibits incest. Intercourse among siblings or other persons related by blood in direct line is punishable by up to three years' imprisonment. The federal government proposed to abolish this prohibition in 2010, arguing that in the few cases where persons were convicted of incest (three since 1984), other sexual crimes such as child sexual abuse were also committed.
Consensual incest between adults is legal in Turkey. Sibling marriage and avunculate marriage is prohibited, while cousin marriage is legal. Marriage between parents and offspring is also prohibited, even when there is no blood relationship, i.e. adoptive parent or parent-in-law.
Legislation regarding sexual offences in the United Kingdom is devolved. Sex with an adult who is related as parent (including adoptive parent), grandparent, child (including adopted child), grandchild, brother, sister, half-brother, half-sister, uncle, aunt, nephew or niece, is illegal. In England and Wales the offence is against the Sexual Offences Act 2003 which effectively replaced the offence of incest with two new wider groups of offences: familial child sex offences (sections 25–29) and sex with an adult relative (sections 64–65). These laws are intended to protect the rights of people, so as to avoid potential violation. However, these laws still outlaw consensual sexual relationships between family members, even if they are fully willing and knowledgeable to the potential consequences. There has been some debate surrounding the rhetoric used by the Sexual Offences Review Team. Roffee discusses how the language used manipulates the reader to deem consensual familial sexual acts as illegal to the point of immoral. In Northern Ireland similar offences are against the Sexual Offences (Northern Ireland) Order 2008.
In Scotland the offence is against the Criminal Law (Consolidation) (Scotland) Act 1995, the provisions of which effectively replaced the Incest and Related Offences (Scotland) Act 1986 (although the 1986 Act was not actually repealed until 2010). Prior to the 1986 Act the law was based on the Incest Act 1567 which incorporated into Scots criminal law Chapter 18 of the Book of Leviticus, using the version of the text of the Geneva Bible of 1562. In January 2016 a petition calling for “Adult Consensual Incest” to be decriminalised, was submitted to the Scottish Parliament's Public Petitions Committee but the petition was not debated and no change was made to the law.
Under Canadian federal law, incest is defined as having a sexual relationship with a sibling (including half-sibling), child/parent or grandchild/grandparent while knowing the existence of the blood relationship. It is punishable by up to 14 years' imprisonment. A person who commits incest with someone under the age of 16 is liable to a minimum imprisonment of 5 years.
Laws regarding incest in the United States vary widely between jurisdictions regarding both the definition of the offense and penalties for its commission. The Laws regarding incest in the United States article summarizes these laws for individual U.S. States and the District of Columbia.
In the United States the District of Columbia and every state and inhabited territory have some form of codified incest prohibition. In most states, sexual activity between a lineal ancestor and a lineal descendant (parent, grandparent with child or grandchild), siblings (brother-sister) and aunt-nephew, uncle-niece is penalized as incest. However, individual statutes vary widely. Rhode Island has repealed its criminal incest statute, and only criminalizes incestuous marriage. Ohio "targets only parental figures", and New Jersey does not apply any penalties when both parties are 18 years of age or older. Massachusetts punishes incest with up to 20 years in prison and the states of Virginia, Nevada, Montana and Michigan provide a penalty of up to life imprisonment for incest.
In some states, sex between first cousins is prohibited (see cousin marriage law in the United States by state for cousin sex, as well as cousin marriage, being outlawed in some states). Many states also apply incest laws to non-blood relations, including stepparents, stepsiblings, in-laws and people related through adoption.
In Argentina, incest is legal if both individuals are over the minimum age of consent. Marriage between 3rd degree relatives and beyond is allowed, with the exception of marriage involving lineal ancestors and descendants, which is considered null and void disregarding the degree of separation (parent/offspring, grandparent-grandchild).
Brazil has no criminal punishment if the involved are over the age of 14 (the clear age of consent in force; before 2011, though, sex with people as young as 12 and as elder as 17 was in a legal grey area, with legal guardian-reported sex with those aged 12 and 13 being prosecuted as statutory rape, but unlike as with those aged 11 and younger not directly prosecuted by the State without a report by either the legal guardians or the adolescents themselves – unlike now, where the police forces prosecute all statutory rape-related cases without distinction –, and legal guardian-reported sex with those aged 14, 15, 16 and 17 being prosecuted as corruption of minors, but prosecution as corruption of minors for non-commercial consented sexual activity between people out of a defined hierarchy fell), capable of acting upon their legal rights, and that consent means that the relationship is absent of any kind of coercion or fraud.
First cousin marriages, once fairly common in some regions in the 19th century, are allowed on demand as all other marriages, while avunculate ones (those between uncles or aunts and nephews or nieces), the preferred by some Amazonian Amerindian tribes, and those between half-siblings, are allowed provided that those contracting it have a health check. Marriages between parents and their children (both consanguineous and adoptive) or between siblings (both consanguineous and adoptive) are invalid, but, as stated above, non-rape sexual relationships between persons older than the age of consent are likely otherwise treated legally as all others, irrespectively of consanguinity (information over the possibility or validity of uniões estáveis in such situations are nevertheless unclear or unexistent, but since those in these relationships are already consanguineous and thus inherently inside a legal family entity, the rights offered by such unions – recognizing a family entity between unrelated single persons – are most likely pointless, with the exceptional cases being only the remote possibility of people who were adopted contracting a relationship with a biological close family member).
Brazilian law, by the Article 1521 of the Civil Code, also extends the invalidity of marriage between parents and children to grandparents and grandchildren or any other sort of ascendant-descendant relationship (both consanguineous and adoptive), parents-in-law and children-in-law even after the divorce of the earlier couple (see affinity), as well as to stepparents and stepchildren, and former husbands or wives to an adoptive parent who did this unilaterally (regarded as an equivalent, in families formed by adoption, to stepparents and stepchildren); and extends the invalidity of marriage between siblings to biological cousin-siblings. It also formerly prohibited the avunculate marriages and extended the prohibition for marriage between siblings to half-siblings, both cited above, but the Decrete Law 3.200/1941 made marriage possible for those non-ascended/descended in consanguinity of third degree (25%) provided both have health checks.
Brazilian law never held marriages between double first cousins as a reason for invalidity, even though those have a consanguinity as strong as that of half-siblings, and those, as other first cousins, are not asked health checks to marry, doing so in the same way as non-related people. Also legally treated much like non-related people are stepsiblings, while those who are stepsiblings and half-siblings (that is, those who have a half-sibling who is also child of a latter married spouse of one's parent) are treated like half-siblings who are not stepsiblings, being demanded health checks before marrying.
In Australia, under federal law, sexual conduct between consenting adults (18 years of age or older) is legal, and state incest laws are subject to the overriding federal law. Federal law prohibits marriage to an opposite-sex ancestor and descendant or sibling (including a sibling of half-blood), including those traced through adoption.
Subject to conflicting Commonwealth laws, incest is a crime in every Australian jurisdiction, but definitions and penalties vary.
In all jurisdictions except New South Wales, incest is sexual intercourse between a lineal ancestor and a lineal descendant. In New South Wales, incest takes place between "close family members", which are "parent, son, daughter, sibling (including a half-brother or half-sister), grandparent or grandchild, being such a family member from birth". Incest generally only applies in cases where a participant is aged 16 or over (the age of consent in that state); and where the participant is aged between 10 and 16 years of age an older participant would generally be charged with sexual intercourse with a child under the age of 16, while cases in which a participant is under 10 an older participant would generally be charged with sexual intercourse with a child under the age of 10.
In Queensland, unlawful incest includes sexual intercourse between an uncle or aunt with their niece or nephew, although here its application is curtailed by the effect of the federal Marriage Act 1961, as the Queensland Criminal Code states that the crime of incest does not apply to “persons who are lawfully married or entitled to be lawfully married”. Thus it is not incest for a niece aged 16 or over to engage in sexual intercourse with their uncles and a nephew aged 16 or over may engage in sexual intercourse with their aunts, but same-sex uncle-nephew and aunt-niece sexual intercourse may be unlawful even in the case of consenting adults, as the Marriage Act does not allow same-sex marriage.
In all other jurisdictions, incest can also arise where one of the parties is below the age of consent, but this does not exclude the possibility of bringing the more general charge of sexual intercourse with a child under the age of 10 (New South Wales and Northern Territory), 12, 16 or 17 (South Australia and Tasmania) as the case may be. This is particularly relevant where a certain form of sexual conduct between related persons falls outside of the legal definition of incest in a particular jurisdiction.
In no Australian state or territory is consent a defense to incest. The maximum penalty for incest varies: eight years' imprisonment in New South Wales; 10 years' imprisonment in South Australia; 20 years' imprisonment in Western Australia and the Australian Capital Territory; 25 years' imprisonment in the Northern Territory, Victoria and Tasmania; and life imprisonment in Queensland. After one conviction for incest, the offender's name is placed on the sex offender registry for 15 years, while any offender with two or more convictions for incest has their name placed on the Register for the remainder of their life.
In New Zealand, incest is sexual connection between a parent and child (both biological and adopted), grandparent and grandchild (both biological and adopted), and full and half siblings.
It is a defence if the person was unaware of the relationship at the time of the act (i.e. accidental incest). A conviction for incest attracts a maximum penalty of 10 years' imprisonment. Incest is the only sexual crime punishable by 7 years or more imprisonment that is not subject to the country's "three-strikes" law.
It is also illegal in New Zealand to have a sexual connection with a dependent child under 18; this includes step-children, foster children and wards. A conviction for having a sexual connection, or attempting to have a sexual connection, with a dependent child attracts a maximum penalty of 7 years' imprisonment.