Mark Thomas has a Guardian piece reacting to some recent genetics promotion in the UK: "To claim someone has 'Viking ancestors' is no better than astrology". It is a good article to share with students because it clarifies some of the possibilities of genetic genealogy from the hype.
My colleague Prof David Balding and I wrote to the BBC and to the two main scientists at BritainsDNA both of whom we knew expressing our concerns about the claims being made. Our expressions of concern over accuracy were met with threats of legal action for defamation by Mr Moffat's solicitors.
Perhaps it is harmless fun to speculate beyond the facts, armed with exciting new DNA technologies? Not really. It costs unwitting customers of the genetic ancestry industry a substantial amount of hard-earned cash, and it disillusions them about science and scientists when they learn the truth, which is almost always disappointing relative to the story they were told.
My advice is consistently: Don't spend money you need for something else, and don't assume that the "interpretation" of your genetics will last more than two months.