Asked by: Charlie Taunton, Leicester
Biometric technologies are designed to recognise you, acting like a password to give you access to a computer system or pass through a security system. Some listen to your voice or examine your signature, some read fingerprints or measure faces, some examine retinas or study your brainwaves, some even measure the geometry of your hands or the shape of your ears.
DNA identification may seem very accurate but only tiny parts of your DNA are examined during a DNA profiling test, and it is easy for samples to become contaminated with other DNA, so it might only be accurate to one in a few thousand.
The most accurate approach will always be to use several methods in combination, because the chances of you having the same shaped face, the same fingerprint and the same retina as another person are infinitesimally small.