- They offer too little value, such as a breakdown of an individual into the categories of "Europe", "Asia", and "Africa".
- They pretend to offer too much value, such as the ability to connect one's Y-chromosome with Old Testament priests, numerous ancient "tribes", or to break down one's genome to a very fine detail that is not commensurate with the power of the DNA evidence they collect (e.g., with the CODIS markers)
Now, they have done it again, pretending to be able to link men with a particular R1b1a2 haplotype with King Tut. Note that the Y-chromosome of King Tut has never been published, and speculation about it is based on some screencaps from a Discovery Channel documentary that may or may not belong to the Pharaoh:
Indeed, the whole business of mummy DNA is highly suspect, as Jo Marchant has covered quite comprehensively in Nature News; see also King Tut's DNA in doubt.
iGENEA was able to reconstruct the Y-DNA profile of Tutankhamun, his father Akhenaten and his grandfather Amenhotep III with the help of a recording of the Discovery Channel. The astonishing result:
The original paper in the JAMA was remarkable for its non-publishing of crucial data necessary to validate the claims within it. This is yet another argument against the flawed peer-review system whose main objective, it seems, is to take in money for journals and dole out prestige to authors, and not to do actual science.
Personally, I'm against most regulation of personal genetics products, unless there is a clear and present medical danger arising from their use: I don't trust government bureaucrats and paternalistic know-it-all scientists to tell us what deserves to be marketed and what does not.
On the other hand, the absence of regulation makes the community's responsibility to speak out against bad products all the more important: such products can only be identified if there is an active and broad group of informed individuals willing to put out the relevant facts out there, and let potential customers decide for themselves.