Incest between twins

Incest between twins is a subclass of sibling incest and includes both heterosexual and homosexual relationships. In traditional Balinese culture, for example, a set of twins of the opposite sex were forced to marry each other, since it was assumed that they had had sex in utero. In Mohave culture, opposite-sex twins were thought to have been married in heaven. Other depictions of or references to it can be found in fanfiction (where it is usually referred to as "twincest"), traditional folklore, erotic and pornographic magazines and videos, advertising, and even mainstream films. In the latter two cases, incestuous relationships between twins are usually only implied and almost always used for a shock effect.

In a review of the scholarly literatures on twin homosexuality and twin incest, Ray Bixler (1983) concludes that "most same sex homosexual twins, if reared with their co-twins, do not attempt or even want to seduce them in adulthood". His study draws on Edvard Westermarck's (1922) hypothesis that sexual desire is generally absent in relationships between members of a nuclear family.

Notable examples in popular culture

 * In Richard Wagner's The Ring of the Nibelung, twins Siegmund and Sieglinde commit incest at the end of Act 1 of Die Walküre. The offspring of this union is Siegfried, the hero of the next operas in the Ring cycle, Siegfried and Götterdämmerung.


 * Incest between twins figures prominently in Thomas Mann's 1905 novella Wälsungenblut (The Blood of the Waelsungen).


 * Luke Skywalker and Princess Leia of Star Wars have a romantic (although not sexual) relationship in Star Wars Episode IV: A New Hope and, to a reduced extent, The Empire Strikes Back. In Return of the Jedi, the spirit of Obi-Wan Kenobi informs Luke that Leia is really his twin sister, and what little romantic interest he still had for her is immediately quelled, replaced by much stronger feelings of fraternal affection.


 * The House of Yes features Parker Posey and Josh Hamilton as fraternal twins Jacqueline and Marty, whose incestuous relationship is complicated by Marty's engagement to Lesly (Tori Spelling).


 * In the 2000 film Cruel Intentions 2, identical twins Alicia and Annie Sorell kiss during a nude shower scene with actor Robin Dunne.


 * Playboy magazine has had a number of twins or triplets as centerfold or cover models, including Mary and Madeleine Collinson, Karin and Mirjam van Breeschooten, the Bernaola twins, and the Dahm triplets.


 * Jirka and Karel Bartok, identical twin brothers, are gay pornographic actors from the Czech Republic who appear together in adult films.


 * In the manga and anime Ouran High School Host Club, the Hitachiin twins are male identical twins, who imply homosexual relationship for the entertainment of yaoi fangirls who attend their host club.