"Women over the age of 40 have a similar risk of having children with birth defects and no one is suggesting they should be prevented from reproducing," said Professor Spencer, whose co-authored study is published in the online journal Public Library of Science.First-cousin marriages were once quite common in Europe, especially among the elite – Charles Darwin married his first cousin Emma Wedgwood – but that changed in the late 19th-century as people, especially women, became more socially mobile and the risks became more evident. You might also be interested in this comment from “The Bible Has the Answer,” by Henry Morris and Martin Clark. Nothing, of course, is mentioned about 4th and 5th cousins which would not be considered a close relative. Also forbidden were marriages to a widowed wife of a close blood relative, that is, a man’s stepmother (v. The scientific reason for this restriction is that children of such marriages are more likely to be deformed or sickly or moronic than those of other marriages. In later generations, brother-sister marriages would come to be recognized as genetically dangerous and would be prohibited as “incest.” Not only the Bible but also most other legal codes refuse to sanction marriages of close relatives.Anything at or above 0.0156, the coefficient for second cousins, is considered consanguineous; that includes relationships between people and their nephews and nieces. For one thing, 25 states ban marriage between first cousins, and another seven states have restrictions on it (for example, in Arizona first-cousin marriage is allowed only if both people are 65 or older, or if one is unable to reproduce).
So let's examine the myths and facts about cousin marriages.Please Note: The information in this article was accurate when it was published.State and county marriage license requirements often change.Dear Daryn, An estimated 0.2 percent of marriages in the United States are between individuals who are second cousins or closer — that means there are about 250,000 people in America in those relationships.I know you asked about first cousins, but all the research I’ve found uses second cousins as the benchmark of consanguinity (more commonly known as intermarriage).Myth and Fact About Marriages Between Cousins In short, yes, it is legal for second and third cousins to marry in the US.