Abortion and the meaning of "human being"

Take a stance on Singer's case (restricting yourself to his discussion on pages 134-136, especially the charge of equivocation). Does the central conservative argument fail? If so, how will this affect the way in which we view the abortion debate? Or can the charge of equivocation be resisted, saving the central conservative argument? (Again, the key point to focus on is the significance of the meaning of "human being" in that argument.) Consider Singer's discussion of the value of fetal life (on pages 134-136 of his book). He argues that different senses of the term "human being" prove to be especially problematic for what he calls the central conservative argument against abortion. (Mary Anne Warren originally makes this point in "On the Moral and Legal Status of Abortion". See the recommended readings for this week in order to access her article.)