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. “As the proportion of the couple’s shared genotypes increased, womens' sexual responsivity to their partners decreased, their number of extra-pair sexual partners increased and their attraction to men other than their primary partners increased, particularly during the fertile phase of their cycles,” says Christine Garver-Apgar, author of the study.

This study offers some understanding of the basis for romantic chemistry, and is the first to show that compatible genes can influence the sexual relationships of romantic couples.

You can request the full study in PDF form by writing journalnews@bos.blackwellpublishing.net.