I think the idea is to spread risk without promoting risk taking, therefore increasing total cost to society. Pricing risky behaviors I'm all for (speeding, accidents, smoking, obesity in most circumstances), as it lowers the cost to society by penalizing the behavior and shifting the burden of the extra risk to the risk taker. With DNA, there is no change in the total cost to be made, the people with the genes will still be around and still need care whether or not you help them pay for it... Unless the goal is to make it more expensive for people with 'bad' genes to procreate. There's an argument to be made for that, but good luck making it...