Biometrics generally involve the capture of just that, a biometric profile of one sort or another. The sort we use with NEXUS, for example, is an iris scan. You can also use one-, five-, or ten-print fingerprints. There is also biometrics involving facial recognition software, which is used by some countries around the world. Those are the typical sorts that other administrations have been using.
On March 12th, 2009. See this statement in context.