Debate exists over whether fetuses feel pain, and if so what to do about it. Because they cannot provide self-report, certitude on the question cannot be reached. The essay argues that a presumption of reasonable doubt is adequate to inform moral behavior. It looks at the most recent evidence from fetal anatomical, neurochemical, physiological and behavioral research and concludes that a reasonable doubt exists that fetuses from 20 to 23 weeks do not feel pain. It proposes that where abortion is legal, providers should be legally required both to provide full disclosure of the possibility of fetal pain starting at 20 weeks and to offer pain-relief measures to suppress fetal pain to all women seeking an abortion.