Natural law says that life begins at conception. It’s also what science says. The liberals say that they determine when a person is created. That, however, is metaphysics. So let’s stick with science, not the liberals religious beliefs
Okay, let's go with your view. Are you consistent? Would you support the prosecution and death penalty for mothers who have an abortion in a society where abortion is banned? If not, why not? You should have no hesitation in doing so.
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Science says life begins even before conception - the semen & the ovum are 'life'. The question isn't 'when does life begin?' or even 'when does human life being?', it's 'when does personhood begin?'.
Pro-life is better re-termed to 'pro-human life'. God made all kinds of life - human life, animal life, plant life. If one is truly 'pro-life', they are vegetarian and don't use any products that require the killing of animal life.