According to Marquis, killing a fetus deprives the fetus of a future like ours in the same way that killing an adult human being deprives him or her of a future like ours. For example, if it were now wrong to kill a 38 year old named Bill because it would deprive him of a future like ours, then it would have been wrong to kill Bill when he was a fetus. Just like Bill now at the age of 38, Bill as a fetus had a future like ours. In fact, he had the exact future like ours as bill as a 38 year old. This is true, even if Bill as a fetus was not a person and even if Bill as a fetus was not conscious.
Marquis is arguing that abortion is prima facie immoral. The conclusion of this argument leaves room for special cases in which the obligation not to kill a fetus might be overridden, such as cases in which the mother's life would be threatened by bringing the fetus to term. But the fact that there are such special cases does not mean that abortion, in general, is morally acceptable. Marquis believes that in the vast majority of cases, abortion is morally wrong.
