Lately there has been a lot of controversy about age verification and it's implementation in places such as UK and US.

The main critic to this mechanism is due being done through facial recognition or a government ID which are privacy invasive.

So here is my question as someone who comes from IT, wouldn't it be possible to create a device which just gives out true or false depending if the person is of age, given some kind of piece of DNA (hair, blood, nails) ?

I known there is carbon dating, but from what I understand is a bit of complicated process. The human body however shows it's age visually and I would be interested to know if genetically there are some signs as well that could be somewhat used in a automatic process.

Again I come from IT, just curious about the implications and your takes on the problem.