New research suggests that choosing a mate may be partially determined by your genes. A study published in Psychological Science has found a link between a set of genes involved with immune function and partner selection in humans.
Vertebrate species and humans are inclined to prefer mates who have dissimilar MHC (major histocompatibility complex) genotypes, rather than similar ones. This preference may help avoid inbreeding between partners, as well as strengthen the immune systems of their offspring through exposure to a wider variety of pathogens.
The study investigated whether MHC similarity among romantically involved couples predicted aspects of their sexual relationship.