Marty Klein has started writing some excellent pieces for Humanist Network News, so it's a shame I'm linking to his latest on abortion only because one of his key points doesn't ring true for me:
The pro-choice position is "I'll behave according to my morality, and you behave according to yours." The anti-choice position is "I'll behave according to my morality, and you must behave according to mine, too."
My pro-choice position is, "Of course I expect others to behave according to my morality, but I don't generally see the termination of a pregnancy as immoral."
The word I use for something I don't expect of others (as in, "I'll behave according to my morality, and you behave according to yours") is preference. My moral sentiments are stronger than mere preferences. Morality is those set of principles of right and wrong I demand, not just of myself, but of everybody. Otherwise, I'd have no grounds to be appalled by others' immoral behavior. We're certainly not willing to allow a murderer to behave according to his morality if it condones his behavior! Regardless of his concept of right and wrong, we see his behavior as immoral and therefore intolerable.
Anti-choicers see induced abortion as the murder of another human being. That we don't share this view doesn't make it any less a moral issue from their perspective. So long as they believe personhood begins at conception, they feel morally bound to oppose all abortion just as we feel morally bound to oppose the murder of an actual person. But it's the belief that personhood begins at conception I see as wrong, not the expectation that others behave according to our own morality.

