In a previous essay , I explored the phenomenon of pedigree collapse as occurred in one of my family lines. Having found another spectacular case of this in a different line of my family, where where one Sara Quackenbush had two parents that were first cousins descended from the same paternal grandparents, and another line where one Anna Elizabeth Kuhn was descended from parents who were similarly first cousins on the paternal line, I must admit that this problem is a lot more common than first believed. I do not believe my own family, after all, to be more prone to first cousin marriage than that of most families around the world. The morals and ethics of the 19th century clearly were far more favorable about endogamy than the contemporary period and that is clearly going to have an influence on family trees.
It is pretty clear given the sorts of jokes that people make about the states where marrying a cousin is legal (mostly in the southern and eastern parts of the United States) that most people are unaware of their own family history and the fact that their ancestors probably married their cousins as well, possibly in multiple generations. People who have awareness of the fact that the past is a different country and that their own ancestry contains some aspects that would not be repeated nowadays are less likely to make fun of others. Not only is the Southeastern United States the most conservative area of the United States when it comes to preserving laws on the books that have long ceased to reflect the normal customs of people, but we know from reading such novels as Mansfield Park (or Pride & Prejudice) and examining the marriage of Charles Darwin to his cousin that this sort of thing happened often enough that it was not viewed as particularly scandalous.
Given the wide derision that endogamy is held in today, it is worth pondering what it is that made endogamy so appealing for so long. In isolated regions where distances are hard, it is likely that marrying among cousins was more or less inevitable after a few generations because of the many connections that had been made over the course of time. Likewise, laws that promoted male primogeniture and that considered the property of females as properly belonging in marriage to their husbands also made cousin marriage far more common, as it allowed families to keep their wealth in-house rather than enriching relative strangers. Similarly, ethnic and religious minorities that find themselves isolated from their neighbors (as was the case, for example, for Jews) also would have been very likely to marry among themselves. Looking at my own family history, it appears that this trend was most to be noticed among people who lived in isolated areas who wished to preserve their cultural identity (usually Dutch or German) in areas far from many other people with that background. Although such concerns are rare nowadays in the United States, they are not ridiculous. If exoticism certainly is something that makes sense to us, surely the love of the familiar and trusted is not to be ridiculed, since it is merely the opposite.
Indeed, the example of the Jews and the biblical patriarchs indicates that religious purity was certainly one of the motives that led people to marry within a close set of people. Indeed, I happen to know personally many members of one particular class of individuals who regularly marry within a very small social circle, namely the children of pastors and local elders of the Church of God, who find their acceptable social circle rather limited to those who are similarly ordained people within the Church of God and who therefore tend to find other members of that same circle to be most acceptable as potential husbands and wives, a tendency that has been reinforced over the last few decades and which tends to build a certain espirit d’corps within this body of people. If such habits are rare in our age where people rejoice in seeing just how far and wide their seed can spread, at least it’s good that a few people understand a sense of restraint.