It's perfectly reasonable to claim their first-generation (genetic) descendants can be expected have at least 25% of the mother's ancestry in each category.
"25%" because some of the supposed ancestry-marking genes that these snake-oil vendors are identifying might appear only on one chromosome of a given pair, and consequently have only a 0.5 probability to be passed on to a given offspring. We can assume that a reputable ancestry-determining organization1 would want a sufficiently large number of markers for any given ancestry characterization that we can expect a return to the average. In practice it should be closer to 50%; 25% is a worst case.
"At least" because the other parent might, of course, have a greater share of ancestry in a given category, boosting the child's.
Now, that might seem like a fairly weak claim; but it is a claim that such a service could report to a subject, about the subject's potential descendants.
1Which these are not. But that's why I wrote "can be expected": if that expectation is violated, it's just more evidence that these five firms are peddling rubbish.
Biting the hand that feeds IT
