Requests by single women for artificial insemination by donor (AID) raise important ethical issues concerning the obligations of physicians and the well-being of the children who would be conceived. Specific objections to AID for single women can be raised, including that the absence of a father may adversely affect the child or that a lesbian mother may influence the child to become homosexual. A review of the relevant social science research indicates, however, that these and other objections are not supported by the available data. In support of AID for single women it can be argued that the life of the child who would be produced could be expected to have value, considered in itself. Consideration of the various aspects of the issue suggests that AID for single women is permissible in selected cases and that the physician has a right to refuse to carry out such requests.