I am assuming that all of Sally's children had the same father, true (I will get to Woodson in a moment), simply because almost all accounts assume she did (or maybe two at most). Certainly, those who sought to clear Jefferson would have pointed out that she slept around if she did- she was a black woman and a slave, and if it were true it would been in their favor to do so. Also, it seems to me that she would have had more children if she was with lots of men- she had, if I recall, six in a period of eighteen years. And again, she only got pregnant when Jefferson was around, despite the fact that during this time he was hardly at Monticello as Sec of State, VP, and President. Now it is possible that she was pregnant more times and suffered miscarriages- but it seems funny to me that babies who made to birth were all conceived while Jefferson was around. In my opinion, Jefferson (Thomas or Randolph or someone else) who she was with was probably the only man that fathered the children, but there is no definite proof. As for Woodson, when I did research on this topic for a school paper sometimes before the DNA results, I read about Woodson. We know that Jefferson fathered Woodson but we assume that Sally mothered Woodson. In fact, there is no evidence of a slave in Thomas Woodson (or Hemings) at Monticello born in 1790. Jefferson kept excellent records on his slaves (which how we know when the other Hemings were born) in his Farm Book, yet he is not in the book. In addition, Madison Heming's account indicates that the baby Sally was carrying upon her arrival in Virginia from France died at birth or soon after. So there is a serious question, IMO whether Woodson is Sally's son.
Unfortunately, we cannot test the other children, since the test requires a unbroken line of Y-chromosomes. Of the five children commonly discussed, Woodson, I already talked about, Beverly and Harriet (as a daughter, naturally there is no Y-chromosome to test) passed for white as adult so their descendent believe themselves to be white and probably have no clue about being a decendent of a black slave. Madison lived as a black person, but his Y-chromosome line was extinguished generations ago. (Although, as the article points out, they still could test the body of his son). Eston also passed for white, but the Jefferson/Hemings story remained in their family so they were easy to find.
Sorry for the long post, I just love history and I am only my vacation from law school, so forgive me. The whole topics is interesting to us, because it is an historical mystery and because to 21th century society, it contains two of the major obsessions of our time- race and sex. But certainly true or untrue it could never diminish the accomplishments of Thomas Jefferson- those are far too important and stand the test of time, long after people stop caring about who he slept with.
Not true. DNA testing showed Woodson was conclusively NOT fathered by any Jefferson male.
There is a William B Hemings, who died in 1910, who could be exhumed and DNA probably obtained (the Jefferson family asked it be done), but the Hemings descendents have said "no."
There is no more reason to believe Sally Hemings had children by one man only than there is to believe she had children by many men. The Carrs confessed to fathering some of the children, and there is contemporary evidence (a former slave's memoir) that Randolph was busy cavorting with the slaves. He was something of a ne'er-do-well in any event. What is more natural and plausable after an evening dancing and fiddling in the cabins than to bed a comely wench? Far more natural and plausable than sneaking down (or sneaker her up to the house) after a formal dinner family and distinguished visitors from abroad. You are correct that we cannot be completely certain, but it seems to me Randolph, who was probably present when Sally conceived Eston, is a far more likely candidate than Thomas.