The transition from innovation to standard of care for maternal-fetal surgery should be guided by ethical as well as scientific considerations. This chapter provides an ethical framework that identifies criteria for the investigation of maternal-fetal surgery. Using this framework, physicians should address the initiation and assessment of clinical trials to determine whether they establish a standard of care, use an appropriately informed consent process to recruit and enroll subjects, consider whether selection criteria should include the abortion preferences of the pregnant woman, and consider whether physicians have an obligation to offer referral to such investigation. This ethical framework, in a clinically comprehensive fashion, takes account of the physician's obligations to the fetal patient, the pregnant woman, and future fetal and pregnant patients. The ethical framework is illustrated by the example of fetal surgery for spina bifida.