Biometrics are the unique characteristics of the individual that differentiate him or her from any other person. Down and Sands explained that the physiological characteristics refer to the inherited traits that are shaped in the early embryonic stages of the human development. Physical biometrics include, among other things, DNA, fingerprints, hand geometry, vein patterns, face structure, skin luminescence, palm prints, iris patterns, periocular features, retina patterns, ear shape, lip prints, heartbeats, tongue prints, and body odor/scent. Behavioral characteristics are not inherited but acquired and learned throughout the life of the individual. These include, but also are not limited to, signature, handwriting, vocal prints, keystroke dynamics, and gait–body motion. As a result, the biometrics of a person cannot be stolen, forgotten, or forged. It is what we are.