The DNA evidence available does not prove Jefferson fathered Hemings children. Therefore some people have hypothesized the father to be another Jefferson, one visiting the household. Apparently they envision Hemings as a freely available amenity, like a candy on the pillow. I have no idea how that wouldn't be worse for Jefferson's humanitarian reputation. Like it or lump it, Jefferson's republicanism had an inconsistency on race, which was merely glossed over.
The endless variety of human beings is such that Sally Hemings may have been bold enough to say no, knowing that Thomas Jefferson would, despite his legal "rights"
, have taken "no" for an answer. She may have been tacitly accepted as a family member (she was if I remember correctly Jefferson's wife's half-sister) and felt comfortable in a kind of sororate marriage in her sister's place. Or she may merely have felt that this way her children would have a chance at freedom, so put up with unwelcome sexual congress, which would not destroy her virtue thus making her worthless. She may even have had sexual appetites that she satisfied by the nearest most attractive male.
Any of these things would have felt less like rape to both parties. None of them may have taken place, and maybe Jefferson bit her breasts and bruised her vagina every time he performed on her, leaving her weeping in pain, fear and shame.
The question is whether an inability to give legally valid consent means any intercourse is therefore rape. By this view, the victim is always nothing but a victim. One implication is that the victim should have been courageous enough to fight back. Another implication is that the victim doesn't have any power at all, which is not literally true, and devalues the humanity of the people. And another implication is that the the victim should have no sexual feelings, which really dehumanizes them.
Also, the black and white view of rape tends to diminish the impact of the term by overuse. Inequality of power is the rule in history and practical constraints on consent are still very common. If a woman having intercourse with a husband she doesn't really love because she's going to keep his paycheck in the family, by this standard she has been raped. But what do we call assaults marked by violence, sexual sadism?
And if we merely go by the legal capacity to give consent, then no Jefferson was a rapist, because Sally Hemings had no consent to give or deny, being a slave. But a horny sixteen year old girl can't give consent, and therefore is raped every time she has intercourse.
Jefferson was a slaver. Every minute he abused every slave he owned. But singling out Sally Hemings as a special victim has more to do with puritanism than anything else.