The New Jersey Supreme Court case that could define the fetus.

The justices, however, seemed skeptical that Rosa Acuna could really have been deceived, however unfortunate Turkish's wording. Didn't Acuna know that being pregnant meant that "in eight months, if there was no abortion, she'd have a baby?" Albin asked.

Yes, she got that, Cassidy conceded. "But she did not know biology." Which took the justices back to where they'd started. Is this case about medical facts, or something else entirely? It's an abstract and frustratingly slippery question. That's why courts often prefer to avoid this territory. If the New Jersey court wades in, it won't just change how doctors in the state talk about abortion. It will change how the rest of us do, too.

Correction, Feb. 26, 2007: The original sentence called the Guttmacher Institute the research arm of Planned Parenthood. In fact, the institute has been an independent nonprofit organization since 1977. Planned Parenthood contributes 4 percent of its budget and appoints four of 42 board members. (Return  to the corrected sentence.)