I think it depends on the application. DNA is being used now in courts and freeing people right and left. But as a practical biometric that can be used in real time -- like a fingerprint to open a door? I think that's a very long way away. It also has unanswered technical questions -- where the DNA coming from, for example.Theta waves -- I don't know. That just makes my skepticism hackles rise. I'm not in the least bit convinced it is a decent biometric, nor am I convinced that it can't be spoofed by mentally singing "It's a Small World" or something like that.
We don't have perfection down on things as simple as fingerprints, so brainwaves seem a little outre me. Take a look at this article, where some Germans manage to be able to fool fingerprint readers, iris scanners and so on. It's downright embarrassing how easy it is to fool these things. I think I'd like to see some of the simpler ones made better before we try things like brainwaves.
For more information on this topic, visit these other SearchSecurity resources:
Tech Tip: Fingerprint scanners can be fooled
Ask the Expert: Fooling a fingerprint scanner
Ask the Expert: Biometrics and Sept. 11
This was first published in June 2002