I feel like that has sort of been asked already, in the context of abortions for women who have been raped/ are in danger. There's quite a few places that allow abortion only in those circumstances, and the reasoning behind that is usually that "fetuses are human, but in these cases the fetus can be killed because it threatens the women/ the women did not consent".

While an interesting avenue to explore, for the general debate it is less useful that discussing when life begins.