4. You're (nearly) immune to an infectious disease. It's good to know when a friend is puking their guts out that I can help take care of them since I'm one of the lucky 20% of white people with wonky fucosyltransferase that won't act as a receptor for the virus.
And knowing (2) lets channel potential anxiety about salt consumption into anxiety about fat consumption, letting me stay healthier on a given anxiety budget.
You still have to pay thousands of dollars if you need the results for actual medical purposes. 23andme only tests for a few of the common SNPs that can cause each disease, but the testing isn't as comprehensive as what you'd get from a doctor.
In the case of cardiovascular disease specifically, one might not want to do that.
This is just to say that that sword has two edges.
EDIT: Made it abundantly clear that this is not my own personal fatalistic perspective.
Just because you're more inclined to do something, doesn't mean you're likely to do something. See the other comment about a 50% increased likelihood moving someone from 1% to 1.5% risk of succumbing to alcoholism.
That said, a lot of people may make the same mistake and succumb to alcoholism erroneously based on the tests.
Let us assume that the absolute risk is non-negligible, and that the predisposition is also non-negligible. Even then, the way that an individual responds to knowledge of genetic risk is idiosyncratic. Some will fight the predisposition even harder, others will succumb even quicker, still others won't know or care.
Because we are talking about the psychology of the individual, and because people do not understand statistics, much less the difference between absolute and relative risk, the fact that the absolute risk for virtually every disease is very small will not matter when an individual considers the issue psychologically.
What does that mean?
If the probability of alcoholism is the general population is 1% ... well, that means yours is 1.5% ... or still ridiculously small.
Obviously those are just numbers I'm using to illustrate a point, but you see where I'm going with this.
1. Genetic disorder. Tay–Sachs, etc. This stuff is priceless, because in the past, you had to pay thousands of dollars to get these same tests tone. These are accurate and very worthwhile ... but the majority of people will come back with all negative results, which is actually a good thing.
2. Your "increased risk" to certain diseases, like heart disease, etc. IMHO, these aren't worth much. A substantial portion of the risk for these types of diseases is related to lifestyle, so take it with a grain of salt.
3. Fun info, like telling you your eye color, where your ancestors came from, etc.
> why are their tests not being subsidized by insurance companies.
Insurance companies really only want #1. And guess what? That's info that I really don't want them to have.