Ya?l: Y'know Don, you've been doing A Moment of Science for a long time now, getting science knowledge out to the public, you deserve a handshake. Don: Uh, no thanks, Ya?l. Y: Why not? D: Well, it's nothing personal, but there're lots of different kinds of bacteria on women's hands. Y: But that's not fair! Men's hands have bacteria, too. D: True, but not as many different types as women's hands. Scientists at the University of Colorado found that women's hands, especially, are just teeming with all kinds of bacteria. They're not sure why this is the case. It could be because the moisture on mens' hands is typically more acidic, and bacteria don't do as well in an acidic environment. In any case, the bottom line is that we have a lot of bacteria on our hands--at least over a hundred different types. Y: Wow! But are all these bacteria a problem? Are women's hands somehow less healthy or hygienic? D: Probably not. Just like we have lots of useful bacteria in our guts, the bacteria on our hands are probably there for a reason. Or, at least, they're not doing us much or any harm. Some bacteria actually prevent the spread of harmful microbes. Y: So, should we be washing with anti-bacterial soap? D: It doesn't seem to hurt. The scientists found that hand washing doesn't really change the diversity of bacteria on hands. Anti-bacterial soap kills most bacteria, but they soon return. Y: So will you shake my hand? D: Sure. Put 'er there.