Editing Incest (section)

====Defined through marriage====
Some cultures include relatives by marriage in incest prohibitions; these relationships are called [[Affinity (law)|affinity]] rather than [[consanguinity]]. For example, the question of the legality and morality of a widower who wished to marry his [[Deceased Wife's Sister's Marriage Act 1907|deceased wife's sister]] was the subject of long and fierce debate in the [[United Kingdom]] in the 19th century, involving, among others, [[Matthew Boulton]]<ref>{{cite book |last=Pollak |first=Ellen |title=Incest and the English Novel, 1684–1814 |publisher=Johns Hopkins University Press |location=Baltimore MD |year=2003 |page=38 |isbn=978-0-8018-7204-4}}</ref><ref>{{cite book |last=Tann |first=Jennifer |title=Oxford Dictionary of National Biography |publisher=Oxford University Press |location=Oxford, England |date=May 2007 |chapter=Boulton, Matthew (1728–1809)|title-link=Oxford Dictionary of National Biography }}</ref> and [[Charles La Trobe]]. The marriages were entered into in Scotland and Switzerland respectively, where they were legal. In medieval Europe, [[Lateran IV]] ruled that standing as a [[godparent]] to a child also created a bond of affinity; which precluded legal marriage.<ref name="b310">{{cite book | last1=Ferraro | first1=J.M. | last2=Pedersen | first2=F. | title=A Cultural History of Marriage in the Medieval Age | publisher=Bloomsbury Publishing | series=The Cultural Histories Series | year=2021 | isbn=978-1-350-17971-4 | url=https://books.google.com/books?id=bqVQEAAAQBAJ&pg=PA133 | access-date=2024-08-23 | page=133}}</ref> But in other societies, a deceased spouse's sibling was considered the ideal person to marry. The Hebrew Bible forbids a man from marrying his brother's widow with the exception that, if his brother dies childless, the man is required to marry his brother's widow so as to "raise up seed to him".<ref>''Hebrew-English Bible'' {{bibleverse||Deuteronomy|25:5–6|HE}}</ref> Some societies have long practiced [[sororal polygyny]], a form of [[polygamy]] in which a man marries multiple wives who are sisters to each other (though not closely related to him).{{Citation needed|date=April 2025}}

In Islamic law, marriage among close blood relations like parents, stepparents, parents in-law, siblings, stepsiblings, the children of siblings, aunts, and uncles is forbidden, while first or second cousins may marry. Marrying the widow of a brother or the sister of a deceased or divorced wife is also allowed.{{Citation needed|date=April 2025}}