The main argument of the anti-choice movement boils down to this: a human zygote, blastocyst, embryo, or fetus is a human being with a right to life, and abortion is therefore murder and should be illegal. This assumption is deeply flawed.
At the outset, let me say that from a pro-choice point of view, the status of the fetus is a peripheral issue. Regardless of whether a fetus is a human being or has rights, women will have abortions anyway, even if it means breaking the law or risking their lives. Even women who believe that abortion is murder have chosen to get abortions, and will continue to do so[1]. That's why we should leave the decision up to women’s moral conscience, and make sure that they are provided with safe, legal, accessible abortions. Because ultimately, the status of a fetus is a matter of subjective opinion, and the only opinion that counts is that of the pregnant woman. For example, a happily pregnant woman may feel love for her fetus as a special and unique human being, a welcome and highly anticipated member of her family. She names her fetus, refers to it as a baby, talks to it, and so on. But an unhappily pregnant woman may view her fetus with utter dismay, bordering on revulsion. She cannot bring herself to refer to it as anything other than "it," much less a human being. She is desperate to get rid of this unwelcome invader, and when she does, she feels tremendous relief. Both of these reactions to a fetus, and all reactions in between, are perfectly valid and natural. Both may even occur in the same woman, years apart.