Decoded: What triggers sexual arousal in you

New York: Know why just looking at an attractive face stimulates sexual arousal? Well, it takes two to tango!

The behaviours like seeing, smelling and sexual arousal that "come naturally and do not have to be learned" occur because of two classes of pheromone receptors that are crucial to triggering the mating process.

In experiments with mice, researchers at the Stowers Institute for Medical Research in Kansas City, Missouri identified that one class of receptors helps a male mouse detect pheromones that indicate when a female is present.

The other class of receptors lets him know if the female mouse is ovulating and ready to mate.

Interestingly, the pheromone that tells other mice that "I am female", or the one that tells others, "I am ovulating", do not do much on their own.

"But when the two are presented together, the male mice showed great interest in courting and mating with the female," said lead researcher Ron Yu from the Stowers Institute.

Pheromones are chemical signals that let an animal know when a suitable mate is near and activate the release of hormones that encourage the animal to mate.

In mammals, the vomeronasal organ, located between the roof of the mouth and the nose, detects pheromones.

Humans no longer have a functional vomeronasal system but the mechanisms that control our inborn behaviour are similar to those in other mammals.

"For example, looking at an attractive member of the opposite sex can stimulate hormonal changes in humans that lead to sexual arousal," Yu said.

The findings offer new insight into how the human brain processes sensory information to elicit courtship behaviours, concluded the study published in the journal eLife.