[benlivengood]

> I'm sure that any of those individuals, once born, would prefer to live regardless of circumstance.

Sure, but if you wait ~5 seconds when trying to conceive a child then that first potential person won't exist and a different one will instead (different genetics and subtly different environments). We always and continuously make choices about which (and whether) potential individuals will actually exist.

As a fetus ages its expectation of existing in the future increases over time but never to the extent that its' mother expects to exist, so expected utility of mothers exceeds fetuses in every scenario.

If we had magical technology we'd simply instantiate all the possible people from scratch and let them enjoy preferring to live. As it is we have to choose the best limited set of individuals who get to exist, and part of that means not allowing a slave class to exist whose sole or primary purpose is reproduction to the exclusion of their own happiness and agency.