All of the books mentioned above and the "false genealogies" that they claim, WOULD NOT PASS "a" genetic test with the families they "supposedly" descend from (no match).
As a serious genealoglist (family), one could immediately see the HUGE GAPS, in the so-called genealogy chart of Pierre Plantard. (especially since on my direct paternal line one of his so-called ancestors is of my father's own paternal line in France ( a line which is well documented historically and legally and by relgious records (mostly Catholic, however some are Huguenot) and that I have personally researched for over 20 years).
By combining genealogy with genetics one can get a "clearer" picture of "who do we think we are".? Together both allow one to have an "eye opening experience" about ones ancestry. People lie, church records have lies in them, (known or unknown). DNA DOES NOT LIE.
Somehow people think that their "known" ancestry', on the y-dna line has never had a non-paternal event (interruption of direct biological male line) such as illegitimacy, known or unknown adoption, assumption of a surname, mother pregnant with child then married another male who on paper is claimed as his/her own, mother is/was married and became pregnant by "another male", (not her husband), change of name, to a variation of name that is different enough that the original surname is quickly lost in a generation or two or in the "mists" of time (such as the French Mainard/Mesnard to the english Maynard/Maynor) etc.
Melusine