Well, people do have 10 fingerprints, but the bigger concern is how easy it is to find them and copy them. They're not secure. You'd actually be much more secure using toe prints as auth tokens, as gross and impractical as that sounds. Most biometrics are lame because they're so readily available. However, they are ridiculously useful because of how fast and conveniently they can authenticate you.

Honestly, this sounds like a much better technology: http://www.dailymail.co.uk/sciencetech/article-3220886/Forge... It transmits data through the human body. You could turn it on or off selectively, authenticate with anything you touch, and it would remain cryptographically secure.