Spouses tend to be more genetically similar than two people chosen off the street at random, according to a new study.

It's likely this is because people who are genetically similar have more opportunities to meet and mate -- in other words, "birds of a feather flock together," said lead author Benjamin Domingue, a research associate at the University of Colorado-Boulder's Institute of Behavioral Science, Newsmax Health reported.

"Genes drive so many things that can structure opportunities and outcomes that determine who we mate," Domingue said. For example, genes may determine whether your potential partner shares your height or weight, or your ethnic background, religion or level of education.

Domingue and his colleagues examined the genetics of 825 white heterosexual American married couples, comparing 1.7 million potential points of genetic similarity.

The results, published May 19 in the Proceedings of the National Academy of Sciences, found that spouses share a significant number of genetic similarities, compared to any two random individuals.

The similarity between married folks is not nearly as deep as that between siblings, though.