zlacker

>>jasonc+(OP)
Sanitation is good, but too much sanitation is not so good. We're only just beginning to understand our relationship with bacteria, virii and micro-organisms. While sanitation was a great boon to reducing deadly pathogens, we're now in the process of swinging the pendulum too far, using antibacterial products that should really only be used in hospitals, keeping children out of the dirt (with growing indications that this leads to allergies), and generally living in fear of anything not institutional-clean. Our immune systems are beginning to atrophy from lack of "exercise".

Have you ever wondered why lovers touch their lips together, effectively sharing the bacterial brew in their mouths with another? I can guarantee that such evolved behavior is not simply coincidental.

>>kstene+kg1
I prefer this much intimate/disgusting/sexier explanation:

"Kissing in humans is postulated to have evolved from the direct mouth-to-mouth regurgitation of food (kiss-feeding) from parent to offspring or male to female (courtship feeding) and has been observed in numerous mammals.[59] The similarity in the methods between kiss-feeding and deep human kisses (e.g. French kiss) are quite pronounced; in the former, the tongue is used to push food from the mouth of the mother to the child with the child receiving both the mother's food and tongue in sucking movements, and the latter is the same but forgoes the premasticated food. In fact, through observations across various species and cultures, it can be confirmed that the act of kissing and premastication has most likely evolved from the similar relationship-based feeding behaviours."

https://en.wikipedia.org/wiki/Kiss#Biology_and_evolution