I must admit I don&#x27;t do a morning scrub-down a la Vincent in Gattaca :)<p>It&#x27;s true that DNA can also be &#x27;non-obviously&#x27; collected. But there are two key differences between DNA and voice auth, when looked at from the perspective of a national surveillance agency:<p>1. &#x27;Non-obvious&#x27; DNA collection occurs after the fact, and is much more costly. You have to send someone to the physical location, collect samples, and process them in a lab.<p>2. Because of (1), DNA could never be used as a &#x27;always on&#x27; mass surveillance system. As opposed to voice auth, where you just need enough microphones, covering enough area, streaming data back to a server for processing. Sorta like how Batman finds the Joker in &#x27;The Dark Knight&#x27; :)