Introduction

The completion of the full sequence of the human genome in April 2003 opened the door to an era of genetic medicine. The sequence makes possible new strategies for understanding and correcting the mechanisms of disease. That same accomplishment, however, also brings forward the possibility of genetic enhancement: interventions that aim to improve health and functioning beyond what has been normal for the species. In the field of sports medicine, there is already talk of turning laboratory research on the genetic bases of muscle function to practical use in athletic competition. "Gene doping" has entered the lexicon of sports writers.

Bioethicists working in the field of genetics long have voiced concerns about the ethics of genetic enhancements, especially those that might be inherited as a result of germ-line gene transfer technologies. They have raised questions about the long-term safety of such interventions, about the viability of consent where cross-generational effects are prevalent, and the possible impact of enhancements on our conceptions of human achievement and excellence. They also have raised questions about social justice. What will inheritable genetic enhancements mean for societies already troubled by pervasive inequalities in income, status, and opportunity? Will enhancement lead to a "genobility"? Must one conclude that this technology is so threatening to social stability that it must be banned?

Each of the three main articles in this issue seeks to challenge one or more of the standard arguments against germline genetic enhancement. Ronald Lindsay's discussion focuses principally on the justice concerns. In his view, we are "ill-equipped" to make firm judgments about the requirements of justice in a society where human nature has been transformed by genetic interventions. Such interventions, he says, "undermine our factual foundation" concerning the nature of future people. This means that society cannot assess the impacts of enhancements on a future society well enough to decide that such interventions should be regulated. It also means that those living in a world altered by genetic interventions may differ so greatly from one another that they are beyond the "circumstances of justice," which philosophers from Hume to Rawls have viewed as a precondition of moral relationships. Lindsay's argument, of course, sharpens the question of whether decision makers should act now to prohibit such radical and unsettling "posthuman" transformations.

Fritz Allhoff challenges all of the standard arguments against, germ-line genetic enhancement. Unlike Lindsay, he concedes that justice concerns might arise, but he believes that future distributive schemes, including some based on Rawlsian premises, could reduce any resulting social problems. He asks whether it is conceptually possible to distinguish genetic enhancements from all the other ways people seek to improve human life and why the genome should be singled out uniquely as beyond human intervention and manipulation. To those who worry about the impacts of genetic interventions on our standards of human excellence, Allhoff asks what could be nobler than the goal of improving human experience.

Coming from a very different direction, Robert Loftis questions the widely disparate attitudes people have toward human and nonhuman germ-line genetic engineering. He observes that although North American bioethicists worry about manipulations of the human genome, they have not shown equivalent concern about the introduction of genetically modified plants or animals in the environment. Yet in terms of the most cogent sources of ethical concern, including matters of safety, justice, and trust, the questions raised by nonhuman modifications are no less worrisome. Both areas, he concludes, merit caution and regulation, but not necessarily outright prohibition.

Two of the commentators who follow are less confident than Lindsay, Allhoff, or Loftis that germ-line genetic enhancement should be allowed to go forward at present, even under the most stringent regulatory regimes. Maxwell Mehlman does not dispute that conceptual and practical difficulties make it difficult to muster support now for such restrictions. Nevertheless, convinced that "unregulated wealth-based access to genetic enhancement could mean the destruction of the liberal state," he urges constant vigilance. Isaac Mwase agrees that the remoteness of risks should not preclude restrictive action now. He insists that our society's moral indifference to present economic inequalities should not be used to justify enhancement-related injustices...