Confucius described marriage as “the union of two surnames, in friendship and in love.” [21] In ancient China, some evidence suggests that, in some cases, two clans had a long-standing agreement that they would only marry members of the other clan. Some men also practiced a soorat marriage, that is, a marriage with the sister of a former woman or a polygynous marriage with both sisters. This would eliminate marriage with cousins as an option, but marriage between cousins would still be acceptable. [22] In the ancient erya system of the third century BC. The words for the two types of cross-cousins were identical, with the father`s brother`s children and the mother`s sister`s children both different. [23] Although it may not have been permitted at the time, marriage to the children of the mother`s sister in the third century CE was also prohibited. possible. [24] Finally, the children and crossed cousins of the mother`s sister shared a number of conditions, with only the children of the father`s brother retaining a separate sentence. [25] This usage has remained to this day, with Biao (表) cousins as “outside” cousins and paternal Tang (堂) cousins from the same house. [26] At certain periods in Chinese history, all marriage between cousins was prohibited by law, as evidenced by the legal texts of the Ming Dynasty. However, enforcement proved difficult, and by the following Qing Dynasty, previous laws had been restored.
[27] Marriages between cousins have genetic aspects that have an increased chance of sharing genes for recessive traits. The percentage of inbreeding between two individuals decreases by four times because the youngest common ancestor goes back a generation. First-degree cousins have four times as many blood ties as second-degree cousins, while first-degree cousins have half the blood ties of first-degree cousins. Double first cousins have twice as many as first cousins and are just as closely related as half-siblings. China has banned marriage to first-degree cousins since 1981. [104] Currently, according to Article 7 of the Marriage Law of the People`s Republic of China, “no marriage shall be contracted under any of the following circumstances: (1) if the man and woman are blood relatives in the direct line or collateral relatives by blood up to the third degree of kinship.” [105] Even without preferential inbreeding, alleles that are rare in large populations may randomly increase at a high frequency in small groups within a few generations due to the founder effect and accelerated genetic drift in a breeding pond of limited size. [212] For example, since the entire Amish population is descended from only a few hundred German-Swiss settlers of the 18th century, the average coefficient of inbreeding between two random Amish Amish is higher than between two non-Amish second cousins. [213] The marriage of a first cousin is taboo among the Amish, but they still suffer from several rare genetic diseases. In Geauga County, Ohio, Amish make up only about 10 percent of the population, but account for half of all special needs cases.
In the case of debilitating seizure disorder, the global total of 12 cases is limited to Amish patients. [214] Similar disruptions have been noted in The Fundamentalist Church of Jesus Christ of Latter-day Saints, which allows marriage of first-degree cousins, 75 to 80 percent of whom are related to two founders of the 1830s. [215] [216] Marriages between cousins remain legal in Germany. In fact, a quarter of all marriages among Turks in Germany are marriages with a relative of the family, according to a survey by the Essen Center for Turkish Studies. [118] Some cultures, on the other hand, may favour marriage between cousins for a variety of reasons. For example, many cultures encourage the marriage of a first cousin to strengthen family ties. Family members who are more closely related share more DNA. For example, your sibling shares 50% of your DNA, while half-siblings only share 25%. Similarly, your first-degree cousin shares 12.5% of your DNA, while your second-degree cousin only shares about 3%. According to Goody, marriage between cousins was allowed in neo-Christian and pre-Christian Ireland, where an heiress was also obliged to marry a paternal cousin. From the seventh century onwards, the Irish Church recognized only four degrees of forbidden kinship and less civil law. This lasted until after the Norman conquests in the 11th century and the Synod of Cashel in 1101.
[93] In contrast, contemporary English law was based on official Catholic policy, and the Anglo-Norman clergy were often disgusted by the Irish “law of fornication.” [94] Ironically, less than a hundred years after the Anglo-Norman invasion of Ireland at the Fourth Lateran Council, the Catholic Church reformed canon law on cousin marriage, with the effect of bringing the doctrine of the Catholic Church back into conformity with the Irish Church and the teachings of the original Christian Church. The teachings of the Catholic churches had proved impractical in practice, as they required people to have all relations with their common great-great-great-great-great-grandparents (i.e., with their sixth-degree cousins) or to buy a dispensation from the Church. Finally, Edward Westermarck noted that marriage between ancient Germanic tribes was apparently prohibited only in ascending and descending lines and between siblings.[95] [96] Cross cousins and uncle-niece unions are preferred and together account for about 30% of marriages in Andhra Pradesh in 1967 and decreased to 26% in 2015-16. [132] These practices are particularly common in rural communities such as the Reddys or the Vellalar, who want to keep wealth in the family. Unlike northern India, this practice is also common among Brahmins in the region. [138] The canonical term for family relationships too close to allow marriage is consanguinity. This is divided into live (grandfather-son-granddaughter) and collateral (uncle-niece-great-niece). Direct line marriages are always invalid. Those in the fourth degree of the collateral line are disabled (Canon 1091), but a local bishop may grant a dispensation for the marriage of first cousins (Canon 1078). For example, the marriage of Louis XIV of France and Maria Theresa of Spain was a first-degree marriage on both sides.
[78] It began to fall out of favor in the 19th century when women became socially mobile.
