An interesting side issue is called pedigree collapse.
When two individuals share an ancestor, the number of distinct ancestors of their offspring will be smaller than it could otherwise be.
The confusion apparently stems from the laws of North Carolina, where double cousin marriage is specifically prohibited, but marriages amongst “normal” cousins (those who are not double cousins) are allowed. Leviticus does deny marriage to “any close relative,” and scholars have long debated whether or not that includes cousins.However, the Bible contains many instances of cousin marriage.This reduction in the number of ancestors is called pedigree collapse.It collapses the binary tree (two parents, four grandparents, eight great-grandparents, and so on in a binary progression).Charles Darwin, who knew something about genetics, married his first cousin, and they raised exceptional children.
All of Darwin’s children were healthy, had no known birth defects, and most of them apparently were either geniuses or near geniuses.Franklin Delano Roosevelt and Eleanor Roosevelt were fifth cousins, once removed (a chart showing their relationship is available at John Adams married his third cousin, Abigail Smith. Fitzgerald, former mayor of Boston and grandfather of John F.One article I read claims that twenty percent of all married couples in the United States are cousins. The only way to find out is to research both of your family trees. In America, marrying your first cousin is legal in 25 states. It is also legal throughout Canada and Mexico to marry your first cousin. Many people believe that the Bible is a higher authority than the laws of men.To be sure, all of us are related to each and every other person somewhere back in history. Some lists claim that 26 states allow cousin marriage. In Leviticus, Chapter 18 (KJV), God tells us that we are not to have sexual relations with a long list of relatives, but the word “cousin” is absent from the list.Couples who are first cousins double that risk to a 4-6% risk.