Whether there is a science behind kissing or if it is merely a learned behavior remains unknown. Nevertheless, there is an actual science of kissing, which is known as philematology. And while these lip-lock scientists attempt to make sense of the act of kissing, London researchers are finding reasons why it's actually a safer way of greeting someone.

According to scientists at the London School of Hygiene, you're more likely to pass along germs and infection by shaking someone's hand than you are by kissing them. Because some people do not properly wash their hands -- which also tend to be the part of the body that is used to touch, carry, or move items (some of which may contain bacteria) -- it's more likely to carry germs on them than it is the mouth.

I'm not saying that you should go and make out with the next person you meet, but this whole issue does point to the importance of hand hygiene in breaking the chain of infection.