The CRISPR Era, the National Academies Report, and the Median Trait Barrier

This chapter begins with the discovery of human gene editing, and how the immediate ethical response used the existing weakened barriers. The chapter then turns to a detailed analysis of how an influential report by the National Academies of Science, Engineering, and Medicine advocated taking down the somatic/germline barrier. The replacement barrier proposed by the National Academies is deemed unstable, and in its place this chapter describes a strong barrier located at the median trait in a population. That is, people could modify their children to take them up to the median value on any trait but not above the median. This would satisfy the dominant contemporary value of justice or fairness, which would require the genetically disadvantaged to overcome their disadvantage, but not allow anyone to use genetics to gain advantage over others.

Introduction

This chapter begins by describing the late 19th-century and early 20th-century eugenics debates from which the contemporary human gene editing debate emerged, and it then brings the debate forward to the contemporary technological possibilities. The chapter introduces the slippery slope, which is the theoretical metaphor for the book. Slippery slopes have the most morally virtuous act at the top and, from the perspective of those at the top, the most reprehensible actions at the bottom. People’s positions tend to slide down the slope. The chapter finishes by discussing how strong barriers can be built on the slope to arrest the slide.

Conclusion

The conclusion begins by summarizing the history of barriers on the slippery slope of the human gene editing debate. A number of more meta-issues that the overall analysis has raised are discussed. First, the chapter analyses whether any barrier can hold in this debate, or whether what is allowable will slide down the slope as our technological abilities grow. The second issue is whether a barrier could be anchored in expertise and authority, instead of rules. This may be possible outside of the United States. Third, the reader is reminded that there is a group of participants in the debate who do not see a slide toward dystopia but a climb to a utopian future. Finally, the chapter discusses generalizations about barriers on slippery slopes that could be applied to other debates.

The First Barriers in the Human Genetic Engineering Debate

This chapter begins with a brief history of the eugenics debates up until the 1950s, when the human genetic engineering debate emerged. Midcentury genetic scientists wanted to make distinctions between themselves and the now vilified eugenicists, so they created two barriers: the somatic/germline and the disease/enhancement barrier. Above both was “somatic gene therapy,” which became ethically acceptable, and the subject of medical research. The chapter continues by showing how these barriers were weakened over the decades by both a change in our scientific knowledge and the dominant values used in the debate. By the end of the 20th century they remained standing on the slope, albeit in weakened form.

Possible Barriers Further Down the Slope

This chapter examines hypothetical barriers on the slope below where the somatic/germline and disease/enhancement walls once were. The first is the goals of medicine barrier, where any trait that the medical profession defines as a disease could be modified. The second is the family genes barrier, where people would be allowed to modify their children to any set of traits that the parents could in principle produce through sexual reproduction. The third is the boundary of humanity barrier, where any genes from outside of the human species are not allowed. Finally, the liberal eugenics barrier would allow any genetic modification that did not harm someone else.