A Reason to Make Out

A kiss puts two people in very close proximity. Our sense of smell allows us to pick up subconscious clues about the other person’s DNA or reproductive status. Biologist Claus Wedekind found that women are most attracted to the scent of men who have a very different genetic code for their immune system in a region of DNA known as the major histocompatibility complex. Pairing off with a male who has a different set of genes for immunity can lead to children that will have a higher level of genetic diversity, making them healthier and more likely to survive. (However, it’s important to note that women who take the birth control pill exhibit the opposite preference.)

Sheril Kirshenbaum explains the benefits of kissing — unless you’re on the pill, then it’s time to stop kissing and dump someone. “Sorry honey, it’s not you, it’s this thing I read online.” [via]