Some time ago, my elder son persuaded me to pay for genetic testing by 23andMe. They send you a test kit, you provide some saliva, they test it. They then tell you what the genetic information implies about medical problems you are more or less likely than average to have and where your distant ancestors come from, and make it possible, if you wish, to get in touch with putative relatives, people who have also been tested and whose genetic information suggests common ancestry not too far back.
They also invite you to answer a bunch of questions about yourself designed to generate additional information about what genetic characteristics correlate with what outcomes, information that can then be used to, among other things, better inform their other customers. Thus getting tested not only provides some private benefits, it also increases the existing store of information about the results of different gene variants, which strikes me as a good thing to do.
I have two pieces of evidence that their service is real. The main one is that they correctly identified my son as my son. The minor one is that they told me I had an above average chance of a particular sort of tumor. The information was not useful, however, since it arrived after the tumor had been diagnosed and removed.
I recently got an email from them, announcing a sale—$99 for their services, which I think is what I paid but is less than their standard price. I thought some of my readers might be interested, hence this post.