I had the idea the other day that perhaps increasing allergy prevalence is a side effect of women taking birth control. Taking birth control causes women to prefer mates with a major histocompatibility complex that is similar to their own, as opposed to different. I'm wondering if allergies are the result of violating nature's usual preference in this regard.

I'm just a layman, so feel free to correct or scoff at the plausability of my pet theory.

http://www.scientificamerican.com/article.cfm?id=birth-contr...