I actually had a startup doing direct to consumer (DTC) genetic testing for a mutation that gave resistance/immunity to HIV. For many reasons, we aren't around anymore, but the reasons included regulatory changes, a rapidly changing market, and ethics. I now feel it's morally wrong to offer these tests to consumers who have no idea how to interpret them and what they mean; at least genetic counseling should be offered with the test. Someone should not make life altering decisions without the consultation of someone trained in the area. For example, suppose someone gets a BRCA 1/2 test, which tests for predisposition to breast cancer. Suppose 60% of those with the BRCA mutation get breast cancer (don't quote me on that figure, but it's in that range). Many women may then decide to get a mastectomy, however, the actual likelihood is much lower than 60% (see Bayes Theorem). Without consultation, they may make a terrible choice, and unfortunately many doctors are not trained in genetics yet.
I've since become involved with a doctor in the Connecticut/New York area who has started a practice centered on genetics. I'm now convinced that this is the only way to go, and that direct to consumer tests are simply a passing phase. 23andme and Navigenics even say that their tests are not medically useful.
I have a blog devoted to this topic if anyone is interested: http://www.thinkgene.com/
and the doctor at that practice also has a blog: http://thegenesherpa.blogspot.com/
In fact, if anyone wants a free genetic test that's better than the one offered by 23andme and Navigenics, and you happen to be in the New Jersey area, Coriell is giving them away (http://www.thinkgene.com/i-spit-at-coriell), and this is where the future of genetics is going.