Criminal prosecutions of women's conduct during pregnancy assume that women have a special duty to the fetus, specifically a legal duty not to harm the fetus. The article argues that the professed goals of such prosecutions cannot be achieved through the criminal law. The offense that pregnant women are thought to commit cannot be defined in terms of any intelligible duty enforceable by the criminal law. Further, prosecuting pregnant women for drug use is unlikely to alter the spread of drugs or the health prospects of children. Instead, it is likely to threaten the rights of women as autonomous individuals and, ultimately, the future of their children. Singling out pregnant women highlights the fact that they are being punished not for any act harming the fetus but because they are pregnant and use drugs. Any rationale that justifies prosecuting pregnant women for risking harm to a fetus may be used to justify controlling all behavior of pregnant women. The article concludes that criminalizing certain conduct by pregnant women is likely to be counterproductive, deterring women from prenatal care and other services that have a realistic probability of improving their children's health. Drug use during pregnancy is a real problem, a public health problem that can only be compounded by treating it as a crime. Notes