[khomenko]

You can. Insurance spreads risk across population pools. You have to carve out those pools somehow, so you use broad variables like age and gender. The problem is genetic information has potential to make the pools too small.

[mikeash]

You don't have to carve out those pools at all. Insurance is workable if everyone is lumped into a single huge pool. The trouble is that a company which is able to break their clientele into smaller pools will outcompete those who aren't, so you get a bit of a race to the bottom.

[khomenko]

Indeed. Singe Payer + Universal Coverage = FTW.

[rscale]

And from a payer perspective, it's problematic if a sizable population secretly learns that they are at meaningfully greater risk of health problems. Those individuals could then adversely select against the payers by buying Cadillac healthcare plans.