We should not let women have abortions, and we should make it illegal

The abortion debate is a morality question. It depends on at what point we assign more weight to the child's right to live than the mother's choices about her health, bodily autonomy, and reproductive rights. There is no hard scientific answer; people will set this threshold differently based on their understanding of what is moral. The best answer is to stand on your own beliefs, since that's all the other side can do as well.