Can Kissing Cousins Wed in the US?

Voice of America, a government-funded multimedia agency, had an article on May 7 about cousin marriage:

A seven-year Columbia University study published in 2018 found that children whose parents are first cousins have a 4% to 7% probability of birth defects, compared with 3% to 4% when the parents are distant relatives who marry.

From 1650 to 1850, the average person was fourth cousins with their spouse, according to the study. By 1950, the average person was married to their seventh cousin. The researchers believe that today, many couples are 10th to 12th cousins.

The data on consanguineous marriage in the U.S. is "scant and incomplete," according to Bittles. CousinCouples.com, a website for people who are romantically involved with their cousin, estimates that about one out of every 1,000 U.S. marriages is between first cousins.

However, Bittles finds that number to be unrealistically low.