So I’m a black American who’s been learning more about my ancestry.

I guess i was wondering about the following scenario:

A mixed race person is born into slavery. This person—under circumstances we don’t have to explore—reproduces with a white person. Their offspring is now 75% white. In my experience this person is probably not white passing, but if they were to reproduce with a white person, their offspring probably would be.

Anyway, I’m kinda describing a hypothetical that would probably happen over many generations and would be very dependent on an individuals phenotypical expression.

But at a certain point, would it be untenable—“ethically” or legally—to keep a person in bondage?

I’m aware of things like the one drop rule, and Im ignoring situations like Sally Hemming’s offspring. Im also aware that a person who looked white enough could probably just walk off. Is that how this would have probably gone?