There are acute risks and long term risks. Yeah it's dangerous to kiss a baby. No one is saying it isn't just as dangerous to bubble wrap them.<p>I wouldn't be so quick to dismiss an evolved behavior. Most likely if the parents are OK with it, and in the absence of major artificial factors, the benefits outweigh the risks. The microbiologists are right, but it's just not the whole picture, it's a small part of the whole equation.