It doesn't matter. He owned her. He could've done anything with her. He could've killed her and there was not a law in the country that protected her and that is the more important dynamic.

Ken Burns discussing his 1997 film Thomas Jefferson and whether descendents of Sally Hemmings are in fact descended from Thomas Jefferson.

According to more recent DNA evidence, they were. Further, Sally Hemmings was in fact a half-sister of Thomas Jefferson's deceased wife. That is to say Thomas Jefferson's father-in-law also had his way with the help. Scratch that, not help, slave.