What makes us fall in love? Is it lust, mutual interests, shared life goals, or something much more intangible? Recent research suggests the latter.

Researchers have only recently discovered an olfactory nerve that they believe is the route through which pheromones are processed. Nerve “O,” as it is called, slipped under the radar for many years because it is so tiny. However, when the nerve was discovered in a whale, scientists surmised that this little nerve might be found in humans as well. And it was!

So what is the role of Nerve “O”? Nerve “O” has endings in the nasal cavity, but the fibers go directly to the sexual regions of the brain. Indeed, these endings entirely bypass the olfactory cortex! Hence we know the role of Nerve “O” is not to consciously smell, but to identify sexual cues from our potential partners.

What sexual cues do our scents give off? For one thing, we are more likely to be attracted to people whose scent is dissimilar to our own. Family members often share similar chemicals, so our attraction to differing chemical makeup suggests that sexual cues evolved to protect close family members from procreating together. On the other hand, pregnant women have been shown to be more drawn to people with similar chemical makeup, which might be due to the fact that during this crucial time, women are more apt to seek out family members than potential mates.

Research has also shown that these unconscious cues processed in Nerve “O” can make or break a relationship. Couples who have high levels of chemicals in common are more likely to encounter fertility issues, miscarriage and infidelity. The more dissimilar your and your partner’s chemical makeup, the better chance you will have at successfully procreating and staying together.

For the complete article, go to http://today.msnbc.msn.com/id/23781652/ns/today-relationships/t/scientists-discover-secret-sex-nerve/