In 2014, Gizmodo had an article about cousin marriage:
In modern western society, marrying your cousin is not well accepted, particularly in the United States. Through a combination of old prejudices and present-day conventional wisdom about inherited birth defects, first cousin marriage is seen by many as a little too close for comfort, as well as a bad idea if you want children.
However, first cousin marriage is far more common, and far less dangerous, than many of us have been led to believe, as you'll soon see. Further, if you include second cousins in the mix, according to the Clinical Genetics Handbook, the increased risks with regards to having children are nearly non-existent in this case compared with non-cousin marriage.
While there have been instances of the banning of marriage between cousins at various points through history, such as the Roman Catholics banning the practice for a time starting with the Council of Agde in 506 AD, for the most part marriage among cousins has been popular as long as people have been getting married. In fact, it is estimated that as many as 80% of the marriages in human history have been between first or second cousins.
