By Emily Murray

It’s hard to deny that some members of the opposite sex are infinitely more attractive to us than others. While our friends may not understand the attraction saying things like “I don’t think he’s cute” or “you can do better,” the throwback to our humble evolutionary beginnings trumps all else. Pheromones, the  chemical odors that play a role in attraction, can override all other attractive or unattractive qualities, baffling onlookers while making perfect sense to the couple. Rather than just looking at someone and finding their physical appearance attractive, the natural odor they emit can cause an undeniable bond and attraction. New research however shows that we may be throwing nature for a loop when we take hormonal birth control pills.

While many of us may have experienced this type of undeniable attraction before, the actual science behind this chemistry may be new to us. More than just a scent, pheromones actually give potential mates a clue as to whether or not their genetic makeup will result in healthy offspring. Those who are most attracted to each other’s natural scents have been found to have complete opposite immune systems which means healthier children. While it may seem a bit frightening that our first thoughts when we meet someone is whether or not they would be appropriate fathers or mothers, it’s a throwback to our earlier roots and something most of us are not even aware of.

So back to the birth control issue.

There were  more than 92 million prescriptions for hormonal contraceptives filled last year according to a recent article in the Wall Street Journal on the topic. For most women, the normal side effects may include things like changes in mood, irregular periods at first…but according to further research, birth control may also sabotage our sense of attraction to others and their attraction to us.

It’s long been known that changes in attraction occur during ovulation, the most fertile time in a woman’s cycle. These changes have been studied on many levels. They not only change men’s feelings toward women, but they also change simple things known to be attractive in women. For example, women unconsciously choose to wear tighter fitting clothing, more makeup and may even be more outgoing and flirty during  ovulation which in turn leads men to be more attracted to them. Traditionally women are also drawn to men with very masculine characteristics during ovulation.

A study tracked this phenomenon in a place where sexual attraction is at the very heart of the business – strip clubs. Dancers who were ovulating actually made far more money during this time than any other time of the month. Again this is a case of our pheromones working overtime in pursuit of a mate while we are, in most cases, totally oblivious.

This being said, birth control changes our normal cycle and even our sex drives. While these contraceptives work very well for those who are not ready to become pregnant, they also have been known to take a toll on libido. Along these same lines, this may be due in part to the change in our own pheromones as well as our ability to become attracted to the pheromones of our mates.

According to the WSJ article –

“Such natural preferences get wiped out when the woman is on hormonal birth control. Women on the pill no longer experience a greater desire for traditionally masculine men during ovulation. Their preference for partners who carry different immunities than they do also disappears. And men no longer exhibit shifting interest for women based on their menstrual cycle, perhaps because those cues signaling ovulation are no longer present, scientists say.”

Of course, humans are pretty complex and often we find studies of our close relatives the primates to be amazing indicators of what is going on in the human dynamic. This is exactly what Duke University researchers decided to test out with a group of lemurs. A group of females was studied both before receiving injections and afterward. The females who were injected with the contraception actually became less attractive to males who had previously shown interest. Apparently the change in pheromones was enough to change the male-female dynamic.

So what’s a woman to do? Researchers say this in no means a widespread cry for women to get off the pill, it’s just one more insight into the art of mating and how science may be interfering in our selection. Once we are aware that these changes are happening, we may be able to make a better decision.