Would this be a concern about privacy exist if there was no way your genetic profile could be used against you? If you couldn't be discriminated in any way on that basis, what else would need to be hidden?
I'm not asking rhetorically -- what else do we have to hide about our genes?
Health may become another kind of risks you can't insure against anymore, like divorce or unemployment.
1) More high risk customers buying the insurance concentrates the 'pool' of insured risks...
2) ...leading to more payouts
3) ...leading to higher insurance
4) ...leading to those without the risks opting to take cheaper, lower level coverage
5) ...leading to more concentrated risk in the pool of insured people in the good coverage
6) ...and back to step 2. The insurance fails, or becomes too high a cost to be worthwhile for anyone.
My point was, no, insurance companies can't use the data, even if they had access to the it, which they won't.
No car breakdown insurance lets you take out a policy to cover the vehicle after it has already broken down...