> Will you please walk me through a scenario that starts with DNA testing and ends with the murder of millions of people?
Imagine a genetic marker predisposes someone towards crime X. Now imagine that in the hands of law enforcement.
If X happens one of the first things they'll do is round up everyone with genes for X and try to place them at the scene of the crime.
The problem with that is that it means nothing. Just because a person is more likely to do X does not mean they've done X.
How do we know that will happen? Because it already happens with DNA evidence today. It weighs far more heavily in cases than it should. It may prove that you were there, but it doesn't show what you did. And that's a problem. Juries aren't generally good at realizing what DNA does and does not show.
You might think "Well, the defense should do a better job at debunking the DNA evidence". Yeah, they should. However, it's a long uphill battle to educate someone. Most people still think lie detectors and handwriting analysis actually work. Hell, many people believe that "essential oils" have mystical healing properties. You want to walk those people through the long process of "correlation is not causation"? Good luck. All the prosecutor has to do is get a DNA analysis finished which proves the presence and a cop to say "Oh, he was really evasive when I arrested him".
The state of our justice system is perfectly summed up by this tweet.
"I actually wore a bandana covering my face, nose down, to go to the bank today. Whole time I'm thinking, 'I've convicted people on less evidence than this ...'", Andy McCarthy [0]
It takes staggering little evidence to convict someone of a crime and the general public sees DNA evidence (due to shows like CSI) as absolute proof of guilt.
This may not be "murder of millions" but it certainly wouldn't be a place I'd want to live. I'd rather not be arrested by a lazy cop because I happened to go to the bank the same day it was robbed.
[0] https://twitter.com/andrewcmccarthy/status/12581541951040184...