Anti-abortion forces have often focused on what one may simply call the anti-killing argument. Killing a human being without justification, mitigation, or excuse is murder. A fetus, or even an embryo, is in relevant respects a human being. Thus [insert obvious conclusion here.] Bracket that argument for a second. My point in bringing it up now is simply to contrast it with a very different argument one has also often encountered in recent decades. I think of it as the natalist argument. It is not pro-life or even anti-killing. It is pro birth. The higher the birthrate the better. In recent years this has often gone hand-in-hand with arguments over social security. "To make social security work, we have to have new young people entering the workforce in a regular basis -- the more of them do so, the more fiscally sound the system is for another generation. The prevalence of abortion (or ready availability of birth control for that matter) limits the number o...