Re:Brave New World... (Score 1)

It gets worse. Everyone's DNA is unique, but DNA fingerprints aren't. In a population the size of Britain, there is a real chance that your DNA fingerprint will be very similar to someone elses.

When you remember that the criminals DNA has to be scraped off the handle of a gun, a doorknob or whatever (so there's a good chance forensics will only get partial DNA) you could end up matching 10 or 20 people in the country.

But most juries are really, really impressed by DNA evidence and tend to forget that there are 19 other people out there who fit the evidence as well as you do.

Especially if you have a history of convictions for drunken brawling outside pubs, or shoplifting

Also there's no special tag in DNA that says "This person committed a crime today". If you collect DNA from a bank right after a bank robbery, you'll get every person who went into the bank that day.

And if Olympic atheletes can switch samples without being caught I reckon the cops might be able to as well. In a number of countries there is a tradition of the cops "helping justice along". DNA testing is so impressive that many people think it couldn't possibly be wrong.