"How can South Dakota claim that you should know separation will kill the fetus, when South Dakota has insisted on informing you, prior to the procedure, that the fetus is already whole and separate?"

Saletan's question obfuscates the distinction between what "separate' means legally and what it means biologically. The fetus is biologically separate, but says nothing about its legal status. Saletan uses the term equivocally.

That distinction matters. The entire theory of abortion is that there is a distinction between biologically-living entity and legal "person." The South Dakota legal warning simply turns that distinction against abortionists. Think about it -- the formal legal warning does not say that abortion is committing murder. It says that the fetus is biologically separate from the mother. It says nothing about the legal status of the fetus, and doesn't claim that the fetus is a legal person. It simply says that the fetus is biologically separate. As for whether the fetus truly is separate biologically, we have a scientific debate. The legal debate follows.

• One objection about the fetus being biologically separate: "Some embryos divide after conception to become two or more people. Are those embryos, prior to twinning, an individual?" No, but whether they become individuals or twins or triplets doesn't matter. What matters is that they become living entities separate from the mother. It doesn't matter how many are separate, the fact that they are separate is the key.

• Saletan offers another objection: “By tweaking a single gene, we're learning to alter embryogenesis so that what would otherwise become an embryo becomes instead a disorganized bunch of stem cells.” Well, sure, but you had to alter the gene to do it. That’s the same as arguing that if the pitch was closer to the plate, it would have been a strike. Well, yeah, but it wasn’t. If you intentionally disrupt the process, the result changes. That doesn’t disprove the process as it originally behaved.

• Another objection: "... the logic behind viability as a standard of abortion jurisprudence: The less the unborn human relies on its mother, the more it encompasses its own developmental program, and the more we should treat it like a born child." Now to be clear, those who argue that the fetus is a biologically and morally distinct person don't, by so doing, disparage the crucial role of the mother in development. But it must be obvious that if there is a crucial difference between saying that the developing fetus, at its earliest stage, requires the mother to do all of the work, versus saying that the mother is alone, and that there is no distinct entity besides her. That entity may be utterly helpless, and the mother’s body is doing all the development work while the entity grows, but that doesn’t logically imply there is no entity besides the mother.

What Saletan fails to discuss is why the warning is given in the first place: to rebut the common misconception that these are just a “bunch of cells.” We can still continue the argument about what the fetus’ legal and moral status is, but from a strictly biologically point of view, these are not just a bunch of cells.