The contraceptive pill may disrupt women's natural ability to choose a partner genetically dissimilar to themselves. This could result in difficulties when trying to conceive, an increased risk of miscarriage and long intervals between pregnancies. Passing on a lack of diverse genes to children could also weaken their immune systems.
Humans tend to be attracted to those with a dissimilar genetic make-up to themselves, maintaining genetic diversity, which is signaled by subtle odors. A research team analyzed how the contraceptive pill affects odor preferences, and found that the preferences of women who began using the contraceptive pill shifted towards men with genetically similar odors.
Not only could genetic 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, researchers said.