The science is irrelevant, you can’t win this argument with the pro life folks. Ask a single question: should a woman who has been raped have the right to an abortion? If they say no, you’re not dealing with a reasonable person. No point into trying, you can only demonstrate to other people just how loony they are. (And a reasonable assumption in this discussion is that they would have the abortion very soon after they discover they are pregnant - not months later)

And if they say yes, goto the next tier: what if her health is at risk, etc