Drawing a line: situating moral boundaries in genetic medicine

Bioethics traditionally focuses on establishing moral limits between different types of acts. However, boundaries are established by communities and individuals who differ in the constraints shaping their moral world. Phase boundaries, the sites of transition between two physical phases such as a liquid and a gas, provide a metaphor for 'drawing a line' in bioethics discourse. Phase boundaries occur where the physical constraints allow both phases to coexist in stable equilibrium. This relationship can also be considered in reverse, using the known position of the phase boundary to disclose the physical constraints. By analogy, instead of trying to locate the 'correct' moral boundary, the alternative perspective of 'reverse ethics' works from a commonly accepted boundary to examine the constraints of the moral world that are being used to establish it. Genetic interventions into the human body provide interesting examples of boundary establishment. In gene therapy, focusing on boundaries has resulted in a model of moral permissibility that ignores some alternative standpoints and increases the potential for conflict between them. Reverse ethics examines such conflicts in terms of the nature of moral worlds that have come into contact with each other, taking seriously the diversity of factors governing the location of a boundary, in ways that might help shift some entrenched lines of conflict.