A biometric is a safety feature based on using "something you are" to confirm your identity. Fingerprints, hand prints and iris scans are all examples of a biometric. All in all, Biometrics help to ensure someone is who they claim to be, because it ties identification to one's physical body, which is the true root of our identities.
The international agreements on electronic passports require a biometric identifier, which is used to verify that the person presenting the passport is really its owner. There is a digital version of the photograph, and following a European Union directive, all EU countries are working to add fingerprint biometrics protected to the epassport. Germany for example already has two fingerprints, one from each hand, in the country's passport. All European Union countries are working to add fingerprint biometrics protected to the epassport, and are currently conducting cross-border tests of these more advanced epassports.
In the United States, visit the government website l and look at the "Apply for a US passport" section.