The prospect of germ-line genetic engineering, the ability to engineer genetic changes that can be passed on to subsequent generations, raises a wide range of moral and public policy questions. One of the most provocative questions is, simply put: Are there moral reasons that can be articulated in general secular terms for accepting human nature as we find it? Or, at least in terms of general secular moral restraints, may we reshape human nature better to meet our own interests, as we define them? This question in turn raises the further question of whether human nature as it now exists has a moral standing akin to sacredness that can be understood in nonreligious terms. This essay will take as a given that it is not possible to show in general secular moral terms that human nature has a sanctity or special moral standing that should guide secular health-care policy. In addition, as this essay shows, it is not possible through appeals to considerations of authorizing consent or beneficence toward others to remedy this failure to establish a sanctity or special moral standing for human nature. Absent a religious or culturally normative understanding of human nature and given the availability of germline genetic engineering, there is a plurality of possibilities for refashioning our nature. The unavailability of substantive secular moral constraints on germ-line genetic engineering discloses a secularly licit plurality of possibilities for human nature. The likelihood that we will be able to refashion our human nature reveals how few general secular moral constraints there are to guide us. Paradoxically, the more we are able to reengineer our human nature, the less guidance is available. The plurality of possible conceptions of human well-being that can be pursued through germ-line genetic engineering challenges our self-understanding as humans. Given human freedom, and in the absence of taken-for-granted religious or cultural moral constraints, the likelihood of germ-line genetic engineering opens the possibility of human nature in the plural.
