It won't harm the insurance companies, as it'll be a level playing field, and they'll all have to simply quote new rates that work out for them given the new data they're allowed to consider. The parties harmed will be, on average, women, whose rates will go up, and the beneficiaries will be, on average, men, especially young men, whose rates will come down.
Oh, good point. Let's also recognize that blacks are more likely to commit violent crimes and have violent crimes committed upon them, so we should be charging them extra for health insurance relative to whites.