One of the things that initially bothered me about the descendants of Robert (1st) Abernathy of Charles City County VA is that until the 3rd generation, there was only one identified son per generation. We now know this can be clearly explained in that the laws then in effect were the ancient feudal BRITISH laws which decreed that all of a man's estate went _only_ to his eldest surviving son.
The present laws of our land owe a great deal to certain ancient Scottish legal practices, and allow an individual to delegate any or all of his estate however he/she wishes, irrespective of what his children may desire.
We can demonstrate some of that with documents left by some of our ancestors, as exemplified by that "Cow Document" wherein the first Robert Abernathy made provisions for a daughter, Sarah. I personally don't believe she was anyone else's child but his, born to his newly married wife Sara Cubishe _before_ they could _legally_ marry because he was still serving his bond servant time when the child was born.
I also find it difficult to believe, in light of the number of children these Abernathys typically had in many subsequent generations, that there was _only_ one child of the 1st and 2nd Roberts. I think there were more. Certainly some daughters, and probably additional sons as well. As proven by several facts, one being that there was a "Willie B Abernathy" in Virginia whom I cannot link to anyone yet but who clearly had a reasonably long life (witness to a will in 1755 and another in 1792). Another being that we now have independent scientific evidence that living male descendants of a) Charles Abernathy who married Alice Short, b) the David Abernathy who married Ann Liles and c) the William Abernathy who married Sarah Doolittle of CT are all actually _very_ closely related to living male descendants whom we can link by documents at each generation as descending from the 1st Robert via 3 sons of the 3rd Robert.
I don't see why the James Abernathy who migrated south into Granville and eventually Tryone County NC could not have been a son of Willie B. who in turn could have been a brother of the 3rd Robert. Or even a 1st cousin.
We have a living, documented, direct male descendant of Elizabeth Cox Mrs James Abernathy who was proven by Y-DNA testing to be every bit as closely related as the living, documented, direct male descendants of any one of the lineages cited.
Why must we link James more closely to the two Roberts who migrated into Granville County NC?Is it not impossible that a younger extended family member could migrate with elder uncles or cousins as easily as with brothers?Why do we almost always assume family members only migrate with brothers and seldom with extended family members?
If we had never considered speculation beyond what previous researcher from the late 1800's had stated as facts, then I, for one, would never have considered a Y-DNA surname project, results of which now prove that no fewer than 16 individuals whose lineages can _not_ presently be completely documented to the 1st Robert. And some of these proven, very closely related, living males have not even carried the Abernethy or Abernathy surname from their diaper days!