Illegal
Legal
Incest, defined as sexual relations between close relatives, is legally and socially forbidden in many countries, but not universally.
In the United States, incest laws vary by state, with differences in legality, punishment severity, and exceptions like Rhode Island and New Jersey.
Internationally, incest laws vary greatly, with some countries like Italy having conditional legality and others like Afghanistan imposing extreme penalties, including death.
Incest is defined as human sexual activity between family members or "close relatives," a term that often includes in-laws, step-parents and step-siblings, adopted parents, and half-siblings as well as the usual aunts, uncles, nieces, nephews, cousins, and siblings. Incest is typically considered socially unacceptable and is legally forbidden in many—but not all countries—worldwide. Some countries have no laws pertaining to incest. Others forbid it between minors, but not adults (or vice versa). Still others allow incest but stop short of allowing the participants to get married.
It is worth noting that most countries that have no laws against incest still prohibit the sexual exploitation of minors. In these countries, relationships between an underaged person (or minor) and an adult are generally illegal whether the participants are related or not, regardless of whether consent was given. Therefore, many forms of incest would be illegal not because they are incestuous but because they are considered statutory rape.
In the United States, laws pertaining to incest vary from state to state. All states have laws that make incest illegal but with a wide assortment of exceptions and/or punishments. For example, Rhode Island prohibits incestuous marriages but has no laws against incest in general. New Jersey tolerates incest provided the participants are at least 12 years of age. In other states, including Idaho, Nevada, and Michigan, incest is not only illegal but can also be punished with life in prison.
State laws typically consider incest a statutory crime and classify it as a felony. Rape and incest are considered separate crimes, as incest includes mutual consent while rape does not. That said, if one participant is under the legal age of consent, the act is generally considered statutory rape (rather than incest) because the underaged participant is legally unauthorized to grant consent.
Incest laws vary from one country to the next, with punishments ranging from minor to severe. For example, incest is only illegal in Italy if it provokes public scandal, in which case it carries a penalty of two to eight years in jail. On the other extreme, incest is punishable by death in Afghanistan, Brunei, Iran, Nigeria, Saudi Arabia, Somalia, the United Arab Emirates, and Sudan (if same-sex relations).
Twenty-two countries around the world have not criminalized incest. Portuguese law, for example, does not criminalize incest. Additionally, no laws prohibit consenting relatives from having sexual relations in France, Belgium, and Luxembourg. Incest is also legal in Argentina, Brazil, India, the Ivory Coast, Japan, Latvia, South Korea, Thailand, and Turkey.
In Spain, Netherlands, and Russia, consensual incest is fully legal. However, siblings may not marry, nor may half-siblings or a step-parent and a stepchild. In Serbia, Lithuania, and Slovenia, incest between an adult and a minor is illegal, but the law does not prohibit minors or adults from engaging in incest with partners in the same age category. Israel outlaws incest among minors but declares it legal if both persons are over 21 years old. Perhaps the most unique laws on incest come from Ireland and Germany, where the language forbidding incest specifically addresses male-female pairings—which means incest remains legal for same-sex couples.
In the following countries, incest is legal: Belgium, China, France, Japan, Latvia, Portugal, Russia (marriage prohibited), South Korea, Turkey (marriage prohibited). Incest is legal for adults only in Argentina, Israel (over 21), Ivory Coast, the Netherlands (marriage prohibited), the Philippines (marriage prohibited), and Spain. Incest is legal in Brazil if over 14 and in Thailand if over 15; however, most marriages in these countries are disallowed or prohibited. Incest is legal in Italy unless it provokes public scandal.
In some countries, incest is legal for adults and legal for minors, but illegal for adults and minors together. These countries include Lithuania, Serbia, and Slovenia. In Germany, incest is legal for same-sex adults (marriage prohibited), but illegal for opposite-sex couples, and illegal but not punishable between minors. Incest between same-sex couples is also legal in Ireland but illegal for opposite-sex couples. In Hong Kong, incest is illegal for close relatives and those under 16, making it legal for distantly related adults.
Incest is not criminalized in Macau, but marriage is prohibited. Incest is technically illegal, but charges can be dropped if all participants are under 18. India does not legally define incest, so it is technically legal; however, it is considered sexual exploitation or rape and is punished accordingly. Both the United States and Australia's incest laws vary by state, but marriage is prohibited in Australia.