ARS Technica has an article about new developments in biometrics.They say scientists are now working on new biometrics systems which analyze your voice:
Voice biometrics is poised to explode in popularity over the next few years because it provides a particularly elegant solution to one of the most basic security problems: knowing whether a person is who she claims to be. Although it's sexy to imagine the technology being used to snag Sinto-speaking con men in Europe, it's banks that are the most ready customers, and some are already implementing it into their telephone banking systems.
Voice can combine what people say with the way that they say it, which means that it provides two-factor authentication in a single action. Fingerprints, iris scans, retina scans, and face recognition can all produce biometric identification (what you are), but something else is needed to provide a second and more secure authentication factor (something you know, for instance). Not only can voice combine two factors, but it can also do so at a distance, normally over the telephone. Remote scanners for the other biometric security mechanisms are expensive and not widely deployed, but phones are ubiquitous, cheap, and well-understood by consumers.