For that specific question, the GINA legislation would be a barrier.

First off it's illegal for them to use genetic information in health insurance decisions in the US.

If it were legal and they did want to do it then why would they need to buy 23andMe to accomplish this? Instead they'd just refuse to insure you without you providing a sample of your DNA.

Making changes to health insurance based on customer genetic information is illegal in the US.

Don't give em ideas man. Next thing you know, your premium goes up by X% because you're predisposed to having an addictive personality and deemed at risk to becoming an alcoholic/opiate/etc. addict.