British researchers from the University of Liverpool (UL) have found that the contraceptive pill appears to disrupt women’s natural ability to choose a partner genetically dissimilar to themselves.
Disturbing a woman’s instinctive attraction to genetically different men could result in difficulties when trying to conceive, an increased risk of miscarriage and long intervals between pregnancies, say the researchers. Additionally, a lack of diverse genes passed on to a child could weaken the offspring’s immune system.
The researchers explained that body odor can play an important role in mate selection. Some of the genes which help build the proteins involved in the body’s immune response also play a prominent role in odor through interaction with skin bacteria.
“The results showed that the preferences of women who began using the contraceptive pill shifted towards men with genetically similar odors,” said UL evolutionary psychologist Craig Roberts. “Not only could [this] similarity in couples lead to fertility problems, but it could ultimately lead to the breakdown of relationships when women stop using the contraceptive pill, as odor perception plays a significant role in maintaining attraction to partners.”