Drawbacks of Biometrics. While we're on the subject, check out this earlier article by Bruce Schneier where he clearly points out two drawbacks to biometrics: 1) although they are unique identifiers, they are not "secrets" and 2) once stolen, a biometric cannot be "re-issued." For enterprise systems that require a high degree of security, such as patient medical records or open systems in FDA-regulated industries, biometric methods should be combined with a second form of authentication, such as digital keys.