Natural Freedom

From an evolutionary perspective, choosing a mate with a different immune system makes survival sense. Kids of parents with different immune genes are more likely to be disease-resistant and are therefore more likely to survive. The women in this study also reported liking the scents that reminded them of their current or previous boyfriends, showing that MHC attraction is consistent. And because MHC profiles differ greatly from one person to the next, there is no universally “good” smell. One woman’s Romeo was another woman’s raunchy.

An interesting exception to the MHC attraction is for women taking the pill. Wedekind found that pill-takers responded in almost the exact opposite manner than would be expected. Because the pill tricks your body into thinking it is pregnant, it chemically alters your sense of attraction. Instead of finding the scent of genetically dissimilar men attractive, women on the pill found the scent of men with MHC’s similar to their own to be attractive.

This may be because when a woman is pregnant, she isn’t looking for a new mate, and may benefit from being around kin, or those with a similar genetic make-up. But, because scent can be such a powerful indicator of a mate that is biologically compatible, what does this mean for women on the pill? Research has shown that picking a mate whose MHC is too similar to your own can result in higher rates of miscarriage and relationship difficulties like infidelity. Are contraceptive takers sabotaging their innate ability to pick a proper mate?