i) Proabortionists often trot out situations where raising the child is a hardship on the mother. And there are undoubtedly situations where that’s the case.
Consider cases where raising the proabortionist was a hardship on the mother. Suppose the proabortionist could step into a time-machine, travel back into the past, and preempt his/her own conception, thereby sparing his/her mother the ordeal of having to raise the proabortionist.
That would be both contraception by time-travel as well as suicide by time-travel. Or suicidal contraception by time-travel. How many proabortionists would step into the time-machine to preempt their conception, so as to spare their mother the onerous experience of having to raise them? How many proabortionists would commit suicidal contraception if they had that opportunity? I daresay not a single one would care enough about the hardship their existence imposed on their mother to prevent their existence from ever happening. Proabortionists are far too selfish to be suicidally altruistic.
ii) Now, I don’t expect proabortionist to admit that. Since it’s just hypothetical, it wouldn’t cost them anything to lie about it. But it’s a way of exposing their hypocrisy.
iii) In addition, sometimes you can plant an idea which will eventually cause a person to change their mind. They may not admit it to you at the time, yet it’s something that never occurred to them, but once the idea is planted in their mind, it works its way through to the conclusion.
iv) A critic might object that my thought-experiment is unrealistic. It generates a classic time-travel antinomy, like the grandfather paradox. But that’s irrelevant. The point of time-travel scenarios is to illustrate a principle in a picturesque way which makes it easier to grasp and appreciate. They can visualize the principle. It gives the principle a concrete setting. But the principle doesn’t depend on the coherence of the illustration. It’s just a fictional story.