This is scary:

If you were going to live to be 100, would you want to know it?

When it becomes affordable to have one’s genome sequenced, perhaps in the next few years, a longevity test, though not a foolproof one, may be feasible, if a new claim holds up. Scientists studying the genomes of centenarians in New England say they have identified a set of genetic variants that predicts extreme longevity with 77 percent accuracy.

If we can identify the genes determining that we'll live to 100, soon we'll identify the genes that determine we die at 55. That's more knowledge than perhaps we need. It's certainly more knowledge than our insurance companies ought to have.