Neither of those scenarios are ideal.
If the only question was genetic differences, that’s a risk I think a lot of people would be willing to take (e.g., that I might be healthy until 100 and then die in your sleep, theretofore paying constantly for others who have had medical problems for 70 years straight). I myself would be willing to take that risk / pay for that style of universal coverage, if not for the aforementioned choice part (smoking, etc.) playing so heavily into the cost, in practice.