You’re right I hadn’t thought of that. You could also look at this the other way. What if Mr Perps dad got around so there are now several children that you would have to seize their DNA in order to find out which one actually did the crime. That would be illegal search and seizure in my book on those sons that were not guilty of any crime.
Exactly. Which is one reason no one is proposing that. Or doing anything at all like that.
The question seems to revolve around privacy of DNA, compared with privacy of facial features. DNA technology, like finger print technology before it, associates identity with small features not easily kept private. You'd have to be pretty careful, and seem a lot like a kook, to keep your fingerprints private from someone who was determined to get them. You couldn't touch your car with your bare hands, for example. In order to keep your DNA private you would have to do God knows what in order to keep from casually shedding DNA from your skin. And you could never give blood, and certainly you could never give a sample for any blood test. Nobody would think anything of it if a witness picked a perp out of a lineup based on facial appearance. And there are laws against wearing masks in public . . .