Actually, my argument isn’t for respecting the rights of the fetus (because we’re not sure if they actually have any), it’s simply for not aborting them. And the capacity for rationality isn’t a “it could have it one day” argument. It’s necessarily tied to whether that thing is a life or not. Which, of course, we don’t know (though god knows people love to pretend like we do). And in the case of doubt, the error should be made on the side of preserving life.