There are many other societies that allow so-called mixed marriages without worrying about genetic defects. And frankly, we have a long history of cousins getting married, take FDR and Eleanor Roosevelt,” he said. While laws against parent-child and brother-sister marriages are based on the almost universal horror with which these marriages are regarded. There is no such strong objection to uncle-niece marriages,” reads Tuesday`s ruling. Avunculate marriages were once common among the royal houses of Europe, as Leviticus 18 was not interpreted as explicitly forbidding a man`s marriage to the daughter of his siblings; In Catholic countries, a papal dispensation could and often was obtained to permit such a marriage. Cousin marriage is a marriage between cousins (i.e. people with common grandparents or people who share other ancestors at a relatively young age). Opinions and practices vary widely around the world. In some cultures and communities, marriage between cousins is considered ideal and actively encouraged; In others, it is subject to social stigma. Marriage between cousins, for example, is common in the Middle East, where it accounts for more than half of all marriages in some countries.
In some countries outside this region, this is rare, but still legal. In others, it is considered incestuous and prohibited by law: it is banned in China and Taiwan, North Korea, South Korea, and less than half of the United States. Proponents of cousin marriages, where prohibited, may view the ban as discrimination, while opponents may invoke moral or other arguments. Worldwide, more than 10% of marriages take place between first cousins or second cousins. In the past, marriage between cousins was practiced in indigenous cultures in Australia, North America, South America and Polynesia. Various religions ranged from prohibiting the marriage of cousins to the sixth degree or closer to the free authorization of marriage to first cousins. Marriage between cousins is an important topic in anthropology and covenant theory. Children from first-degree marriages may be at increased risk of genetic disorders, especially if their parents both carry a harmful recessive mutation, but this can only be estimated empirically, and these estimates are likely to be specific to certain populations in certain settings. Children of more distant cousins have a lower risk of harmful genetic mutations. In fact, a review of Icelandic records found that marriages between third or fourth cousins (people with common great-great-great-great-grandparents or great-great-great-grandparents) can produce the most children and grandchildren. Partners in an avuncular marriage have the same genetic relationship as half-siblings or grandparents and grandchildren, sharing an average of 25% of their genetic material.
This is more than that of a first-degree relationship, in which members would share an average of 12.5% of their genetic material, but less than that of full siblings. Avunculated marriage was the preferred type of union in some pre-modern societies. Marriages between such close relatives were common in ancient Egypt, at least among members of ruling dynasties. A broken marriage is a marriage with the brother or sister of a parent or with the child of a brother or sister, that is, between an uncle or aunt and his niece or nephew. Such a marriage may be between biological parents (related by blood) or between persons who are related by marriage (affinity). In some countries, avunculated marriages are prohibited by law, while in others, marriages between these biological parents are both legal and common, although they are now much less common. [ref. If the partners in an avunculated marriage are biologically related, they usually have the same genetic relationship as half-siblings or grandparents and grandchildren — that is, they share about 25% of their genetic material.
(They are therefore more closely related than partners in a marriage between first-degree cousins, in which members share on average 12.5% of inherited genetic material, but less than in a marriage between, say, cousin-siblings, in which partners share 37.5% of their inherited genetic material.) Avunculated marriage was common among South Indians. Currently, it is practiced mainly in rural areas and small and medium-sized cities. The most common form is when the eldest daughter is married to the youngest uncle on her mother`s side.  The marriage is usually referred to as Mama Kalyanam (Thai Mama Kalyanam in Tamil Nadu). It was culturally preferable for at least one girl to be married to an uncle. This is widely used as a plot tool in many South Indian films such as Thaamirabharani and Thai Maaman.  Avunculated marriages were important in the House of Habsburg. For example, Charles II of Spain was the son of an uncle and niece, Philip IV and Marianne of Austria; In turn, both of Philip`s parents (and thus both maternal grandparents) were the children of uncle-niece marriages, one of which also produced Mariana`s paternal grandfather.
As a result, Charles` parents, grandparents, great-grandparents and great-great-grandparents numbered only 30 different people, but only 23. Avunculated marriages are currently illegal in most English-speaking countries, but allowed in Argentina, Australia, Austria, Brazil, France, Malaysia and Russia.  Avesdropping marriage is the preferred type of union among the Awá-Guajá of the eastern Amazon.  This is also a fairly common practice in the southern Indian states of Andhra Pradesh, Tamil Nadu and Karnataka. Related category: Blood marriage If a married couple has one or more common ancestors, their marriage is considered to be related by blood. Depending on the degree and nature of the consanguinity and customs at a time and place, their marriage may be normal, even beneficial, frowned upon or prohibited. The law states that “a marriage is incestuous and void, whether the parents are legitimate or illegitimate between: 1. an ancestor and a descendant; 2. A thoroughbred or half-blood brother and sister; 3. An uncle and niece or aunt and nephew. When people are more mobile and live longer, marriages end and people remarry and you get mixed families with stepchildren and half-children,” Stutman said. The state appeals court ruled Tuesday that the 14-year marriage of a Rochester man and his Vietnamese half-niece was legal under state law.
The decision is one of the few that affects the marriage of a half-uncle or half-aunt to a half-niece or half-nephew in the state, as such marriages were made illegal more than 100 years ago. Laws prohibiting marriage in all 50 states, the District of Columbia and two territories have been classified as those that include direct and collateral categories of relatives, and those specific to linear, collateral, and affine parents. A person is not allowed to marry his parents, grandparents, children or grandchildren, except in Georgia, where a man is not prohibited from marrying his daughter or grandmother. Although all political entities prohibit marriage between a person and a brother or sister, aunt or uncle, their prohibitions vary widely for other degrees of collateral relationship. Uncle-niece marriage is not prohibited in Georgia and among the Jews of Rhode Island. In general, marriage between persons with a kinship coefficient corresponding to or closest to first-degree cousins was prohibited. Less than half of the political divisions banned affine parents. In societies adhering to the Jewish or Christian faith, such marriages were sometimes permitted. The Talmud and Maimonides encouraged marriages between uncles and nieces, although some of the earliest Jewish religious communities, such as the Sadducees, believed that such unions were forbidden by the Torah.  Among medieval and especially modern Christians, marriage between a woman and the brother or sister of one of the parents was not always interpreted as a violation of Leviticus 18; this was particularly the case among the royal houses of Europe, and in Catholic countries a papal dispensation could be obtained to permit such a marriage. In 2007, their bond was brought before immigration officials who tried to send Nguyen home by annulling the marriage. The 2nd District of the U.S.
Court of Appeals then asked the state`s highest court for its opinion on the legality of the marriage. This page contains descriptions of different forms of marriage with different levels of legality around the world. In Catholic countries, exemption was required before 1918 for marriages up to the fourth degree of consanguinity, and after that date for marriages up to the third degree. Since any marriage that could be permitted received a dispensation even in Catholic countries, this requirement was only a formality and did not prevent marriage between cousins where culture permitted or encouraged it. In Sicily, and especially in the provinces of Palermo and Agrigento, dispensation was required in up to ten percent of all marriages in the early twentieth century. (Luigi Luca Cavalli-Sforza, Antonio Moroni and Gianna Zei. “Inbreeding, inbreeding and genetic drift in Italy.” 2004: Princeton University Press.) Such marriages are traditionally illegal in Islamic societies and are considered forbidden by Islam.  There are now fewer restrictions on marriage in New York, although the change is probably not what you expected.
Direct ancestral marriages (father-daughter, grandfather-granddaughter) and fraternal marriages are taboo almost everywhere. However, other close marriages, such as between uncles and nieces or between first cousins, are common.