Research conducted on over 800 husbands and wives shows they have pretty similar DNA.
Behavioural scientists from the University of California said that their findings can partly be explained by people who marry within their same ethnicity or marrying someone living nearby, or because people with similar genes may share the same interests or hobbies, according to The Daily Mail.
It is not known how people select the right match with genes, but it could be as simple as being attracted to someone of a comparable height, said researcher Ben Domingue. Domingue’s findings conflict with earlier research on the theory that opposites attract. That theory says that we seem to be attracted to people with very different genes and immune systems, which would provide children with immunity against a broader spectrum of diseases.
But another study done in 2010 at Michigan State University supports Dominigue’s research and showed that people tend to marry people with similar tastes and traits, so many married couples really are two peas in a pod.