… kann man bei howstuffworks.com erfahren:
When you really think about it, kissing is pretty gross. It involves saliva and mucous membranes, and it may have historical roots in chewed-up food. Experts estimate that hundreds or even millions of bacterial colonies move from one mouth to another during a kiss. Doctors have also linked kissing to the spread of diseases like meningitis, herpes and mononucleosis.
Yet anthropologists report that 90 percent of the people in the world kiss. Most people look forward to their first romantic kiss and remember it for the rest of their lives. Parents kiss children, worshippers kiss religious artifacts and couples kiss each other. Some people even kiss the ground when they get off an airplane.