Yeah, the evidence that fingerprints are unique isn’t even there. We know they are usually pretty different, but when databases get big you have to start thinking about actual uniqueness. They say the chance of a DNA sample randomly matching another person is less than one in a million, but they’ve got more than a million DNA samples in the database. So DNA is still pretty good, but if you get a DNA match for someone who doesn’t appear to have anything to do with the situation and you can’t find any links, it’s not unreasonable to think of randomness.
Of course, that’s ignoring human error. When someone says something has a one in a million chance of being wrong, I want to say, “So you’ve done this over a million times and no one ever made a mistake?”
