The Law of Data Entropy
AKA the second law of data dynamics:
"whenever data distribution is out of equilibrium a potential or data-dynamic "force" (the gradient of a potential) exists that the world acts spontaneously to dissipate or minimize."
So you give DNA samples to a 'database' which is used for the police to investigate crimes. That creates an inbalanced equilibrium, why can't the prison services have it too?, the tax man?, insurance companies?, me, ME?! What if my kids are in your nursery school and you have a genetic disposition to psychotic freak outs? I DEMAND THE RIGHT TO SEE YOUR DNA RECORDS! Just like a similar bloke like me in an insurance company can see it.
Ahh, but I don't have kids, but if someone with kids can see your DNA records why not me?