I’ve told Mr. B. that he can legitimately claim an African-American ancestor. It would work as an Affirmative Action gambit these days if that should ever be needed. IF, that is, we buy into (or pretend to) the widespread claim that South Carolina planter/slave owner Gideon Gibson was a mulatto.
He was, indisputably as far as my family is concerned, our six greats uncle because we descend from his sister Hannah Gibson and her daughter Marcia Saunders Murphee.
Marcia (nicknamed Massey) married Claudius Pegues III Jr., a disabled Revolutionary War veteran and my four greats grandfather whom my late mother (and subsequently one of her granddaughters) used to establish membership in the Daughters of the American Revolution.
Although if mother knew anything about Hannah and Gideon Gibson she never spoke of them to me. Neither the African nor a possible Jewish connection would have appealed to her, to put it politely.
I prefer the claim that these Gibsons (sometimes spelled Gupson) were, in fact, Sephardic Jews, possibly originally from Portugal. Not that such exalted sources as PBS and Tulane University would necessarily agree. Indeed, large numbers of African Americans claim descent from Gideon and we know what openly daring to disagree with black people will get you nowadays.
But genealogy is very far from an exact science, and other than establishing a link to a person, old (and frequently misspelled) public and private records are at best ambiguous—we have no idea, for instance, whether Gideon called himself a mulatto, or whether some officious British colonial clerk decided he was one based on his skin color, hair texture and/or facial features.
We do know that Gideon carried documents proving he was a free man, because he showed them to the then governor of South Carolina (1740s), which was duly recorded, but the documents could as easily have been his release from indentured servitude—rather common in his time—as any manumission from slavery.
So we are pretty much left to believe what we like. And what I like is the idea that Gideon and Hannah Gibson were not half or less Africans at all but Melungeon Jews, Sephardics in flight (and often in secret) from the Catholic Inquisition which had driven their ancestors from Spain and Portugal.
Although I’m sure the African claim would make a much better Affirmative Action gambit than the Jewish one.
THE TEXAS SCRIBBLER 
The story of Melungeon Jews sounds interesting. But Lincoln? I always thought it’s a joke…
The Melungeon Jews (Sephards and Crypto-Jews fleeing the Inquisition) seem indisputable to me, with the proviso that not all Melungeons were Jews. I agree that the Lincoln connection probably is a stretch. Have seen similar claims, including Thomas Jefferson and Jefferson Davis. It’s an old preoccupation of some ancestor hunters to try and link themselves to the famous.
I am a direct descendant of Gideon Gibson. He was my 8th great-grandfather on my mother’s side. I have conducted a little bit of research on him and the only information regarding his “mulatto” status I could find was, as you mentioned, a court document stating he was free. I believe this characterization of him as a mulatto was simply the result of an official looking at him rather than asking him. I did find his name listed several times in the JewishGen.org “Family Tree of the Jewish People” database. This, of course, does not prove his Jewish ancestry, but might work in favor of it. If we could simply find a direct male descendant, we could find out if there is any Semitic DNA haplogroups. Given the time period and his circumstances, I lean more towards Sephardic Jewish ancestry. If you would like to contact me, please send me an email, as it seems we are related via Gideon.
Also, Sephardic Jews tend to have medium to dark skin tones and thicker, curlier hair as opposed to their Ashkenazi (German Jew) counterparts. This, in my opinion, is why he was classified as mulatto.
Thanks for the comment. I will email you when I get a chance later today. Something not here that I found later is that Gideon seems to be descended from one Thomas Gibson, a merchant (tradesman, it was called in those days) who arrived in the second resupply ship at Jamestown, Virginia, in 1608. Which doesn’t overrule the idea that he might have been African but it doesn’t seem likely. Although I have read that there were free Africans in the early colonies. Not so much racism in those days as later when the slave owners had to justify the institution in the face of abolition’s growing tide by contending blacks were ignorant savages, etc., even as some of them were skilled craftsmen on the plantations..