Marrying of Cousins

In a 30 December 2016 post on his blog, Genealogy’s Star, James Tanner discussed whether there is a prohibition of cousins marrying: Can you marry your cousin? What is or was the law?

James described what the current law is in Utah, where he lives. He also cited the restrictions imposed by the Roman Catholic Church under Canon Law. In both instances marriage is prohibited between first cousins, except in very unusual circumstances.

I wondered what the rules were for the Church of England, particularly in the 18^th and 19^th centuries, since I have a few examples in my family of first cousins marrying, including my own 4^th great-grandparents – married in 1791 in Devon, England. I had thought about the question before but had not bothered to look up the answer.

In my search for information I came across a paper on the subject by Jill Durey, The Church, Consantuinity and Trollope, in the Churchman, v. 122 (Summer 2008), pp. 125-46. The Churchman is the international journal of theology produced by the (Anglican) Church Society.

The Church of England, of course, was set up in 1534 specifically to allow Henry VIII to dump his first wife and marry a cousin. He employed some devious means to get around the prohibitions of the Catholic Church, setting up his own church with different rules on the matter of marriage. In so doing he had his daughter, Mary Tudor, from his first marriage, declared as illegitimate. (She eventually got her own back after taking the thrown, when she annulled Henry’s “divorce.” But that’s another story.)

In any event, as part of the establishment of the Church of England, marriage between cousins was allowed. Over the years there have been other Church of England regulations that controlled who could marry who. I blogged about one such example, on 15 September 2013, of a man who married his deceased wife’s sister – Mistaken Assumptions from Register Notes.

List of prohibited unions in Church of England, and the changes made over time: Genetic and Quantitative Aspects of Genealogy website - No cousins are mentioned.

There have been many studies about whether cousins marrying have an adverse biological effect on offspring. Certainly inbreeding over long periods of time can lead to unwanted and undesirable physical and or mental conditions. Recessive traits can manifest themselves because the genetic makeup of the individuals is similar. Offspring may be more likely to exhibit conditions that might otherwise be overridden by more dominant traits. Where a family has no prior history of birth defects or other deleterious conditions, though, it is unlikely they would appear because of the union of closely-related cousins. It is possible children may actually be healthier as a result of inheriting strong attributes from both parents having similar familial traits.

The idea of prohibiting the marriage of related people, of course, developed within small tribes or communities to prevent inbreeding over several generations and a general deterioration of the gene pool. It was a practice decided long before the study of genetics but it was solidly based on observation. At any rate almost every religion organized since has kept the policy in the form of rules under which adherents must abide.

King Henry made the exceptions acceptable by replacing the dominant religion in his domain with a new one, certainly with his own personal intentions in mind. The result was that the prohibition of cousin marriage was made acceptable for the first time in Europe. It had long been allowed in Middle East. Marriage of cousins was also permissible, and widely practiced in China for many centuries, but has been banned under the current regime. In many parts of the world culture plays at least as strong a role as religion.

In the United States the rules are very different from state to state no doubt based on the views of the original settlers.

In Canada, the law is relatively simple and parallels, as one might have assumed, the rules of the Church of England: “…persons related by consanguinity, affinity or adoption are not prohibited from marrying each other by reason only of their relationship, but no person shall marry another person if they are related lineally, or as brother or sister or half-brother or half-sister, including by adoption.  A marriage between persons who are related in this manner is void.” From Marriage (Prohibited) Act.

As James Tanner pointed out, the subject is worth investigating in the various parts of the world where family research is being undertaken in order to understand the legalities of inter-cousin marriage but in particular how local rules may have impacted particular family members.

Other References:

See these articles for more references on the subject.

Cousin marriage (Wikipedia) The maps shown above were sourced from this website.

Prohibited degree of kinship (Wikipedia)

Wayne Shepheard is a volunteer with the Online Parish Clerk program in England, handling four parishes in Devon, England. He has published a number of articles about various aspects of genealogy in several family history society journals. He has also served as an editor of two such publications. Wayne provides genealogical consulting services through his business, Family History Facilitated