Being someone is the question and an ancient one and the crux of the matter, at what point does a thing become someone? That is the moral question and the correct one to ask, logic and science can inform it, but it is the same one as the difference between sapience and sentience, one we eat and also love (as in pets), the other has legal and social statues, along with rights. It is not strictly a legal or logical question either, but the feelings and emotions that drive us and human beings are involved too. Altruism is hardwired into humans and to deny it is to deny our humanity.
A women's right and ability to choose her fate diminishes with the progress of the pregnancy in almost all cases, even in places with liberal abortion laws.