Why opposites attract romantically

Just in time for Valentine's day:

New Study Is First To Link Romantic Relationships To Genes

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.

On the other hand... While this may apply to non-human mammals like mice and chimps, there could be trouble in our species with parters who are too opposite. If she prefers classical music, luxury cruising, a neat and tidy house, and eventually wants a large family, while he prefers hip hop, mountain climbing, a relaxed attitude towards domestic order, and doesn't care that much for kids, there could be trouble brewing.

Even if they have great sex together.