A large problem in trying to debate abortion is that the pro life argument often boils down to "It makes me uncomfortable/God says no, therefore no one should be allowed to do it."
Disliking something is generally a good reason not to do something yourself, but not to prevent other people from doing it unless you can show that it really would make their lives better/safer etc. And, to the apparent chagrin of "pro-lifers", there isn't sufficient evidence to show that banning abortion is an improvement for anyone except themselves. A small minority (5% IIRC) of women regret having an abortion. For the remainder, it has prevented them having children they cannot afford to raise or would be unable to raise in a safe environment or who they just have no desire to have. Societally, it means fewer children born into poverty, fewer women tied to abusive husbands through children, fewer women left disabled or chronically injured from pregnancy and birth, fewer women dead through illegal abortions, fewer children born to incapable or unwilling parents. The knock on effects of these are massive and overwhelmingly positive.
It's a free country. People can argue that they don't like it/God doesn't like it/ think of the poor ickle zygotes all they like. But in a country with neither a strong authoritarian bent and desire to repopulate, or a strong religious persuasion, they aren't going to be taken very seriously because their arguments lack substance.