LiveScience makes clear that sometimes, contraception isn’t the best decision. Or, well, doesn’t help you make the best decisions… because birth control pills befuddle women’s mate radar:
That’s because beneath a woman’s flowery fragrance or a guy’s musk the body sends out aromatic molecules that indicate genetic compatibility.
Major histocompatibility complex (MHC) genes are involved in immune response and other functions, and the best mates are those that have different MHC smells than you. The new study reveals, however, that when women are on the pill they prefer guys with matching MHC odors.
This might explain quite a few confusing bits of the latter half of the 20th century.