Collegiate Times

Often, the first thing we notice about people is their physical appearance, and while it's often regarded as a shallow way to assess a person's attractiveness, it is nonetheless guided by natural instinct.

Personality and sense of humor are also important factors that play critical roles in determining who makes your heart beat faster.

However, many of these factors contribute to sexual attraction, and quite a bit of speculation and controversy surround the possibility that there may in fact be real "chemistry" behind Cupid's ability to pair us up with that special someone. In order to find the key to how science influences sexual attraction, perhaps we should just follow our nose.

Pheromones have long been identified as chemical substances naturally emitted by the body that play subtle roles in triggering behavioral and even physiological responses between members of the same species.

The use of pheromones by insects to communicate, warn and mate is well studied, but much less is known about how pheromones may affect human interaction. One of the world's most prominent researchers on this particular topic, Martha McClintock of the University of Chicago, has collected international acclaim for her work investigating pheromones on human sexual desire and reproduction.

In 2002, McClintock and a team of researchers discovered that depending on their genetics, women may be attracted to certain men rather than others simply by their particular odor.

Using previously worn T-shirts, the study found that women were attracted to the aromatic compounds produced by men with whom they shared a similar, but not identical, genetic make-up, and were least attracted to those of men with whom they were most dissimilar. "Women can actually smell genetic differences," said McClintock in a press release following the study. "They can smell differences as small as a single gene." Incestuous couples and isolated communities with narrow gene pools have been known to have more miscarriages and children with recessive genetic disorders.

Therefore, this "scent-based" method of mate selection might provide an evolutionary advantage to our species by helping to maintain genetic variation by preventing family members from bedding down with one another.

Co-author of the study, Carole Ober, professor of human genetics at the University of Chicago, followed up by saying, "This finding provides a mechanism for understanding, in part, the biological basis for several human social behaviors, possibly including relationships with siblings, friends and even mate selection."

Fast forward two years, and McClintock and friends have discovered something equally as interesting. For two months, a group of women were subjected to chemical compounds released by breastfeeding mothers and their infants.

Those with regular sexual partners experienced a 24 percent increase in sex drive after exposure to the compound, and those without partners noticed an increase in their subsequent sexual fantasies. "This is the first report in humans of a natural social chemosignal that increases sexual motivation," said McClintock.

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