The right of pregnant women to refuse obstetric interventions is an established tenet of obstetric ethics. However, that does not mean that fetal considerations are inconsequential. Although respect for negative autonomy is largely a settled issue, what is less clear is the degree to which a pregnant woman's affirmative autonomy (the right to demand) should be controlling. We discuss the ethical basis for deciding when a pregnant woman's affirmative autonomy should be decisive. We focus on the ethical consequences when a fetus is considered a "potential child" because of a woman's decision to continue a pregnancy. Her intention determines the relevance and nature of the interests of the future child. Although fetal interests may temporally approach those of a born child, they are, in all cases, still circumscribed by the de facto circumstance of the potential child, ie, the child cannot be treated without treating the mother. That treatment would implicate the pregnant woman's right to bodily integrity. This right is so fundamental to our conception of autonomy that its trespass should give serious pause to all who respect basic human dignity. Accordingly, the future interests of a child should not constrain a pregnant woman's right of negative autonomy (the right to refuse any intervention intended for the putative benefit of the fetus or herself). However, the interests of the potential child may factor into considerations of affirmative autonomy and, in parallel, on a physician's right to refuse a particular intervention or plan of care.