Trojan Horses, Clinical Utility, and Parfitian Puzzles.

Abstract

There is a burgeoning corner of the philosophical literature on germline gene editing (GGE) about whether GGE is “person-affecting” or “identify-affecting.” The distinction between actions that affect the welfare of future persons, and those that determine which future persons exist at all, is due to Derek Parfit, and is the source of a major puzzle widely discussed in the practical and applied ethics literature on several issues (Boonin 2014). The major aim of Robert Sparrow’s (2022) “Would Genome Editing Harm or Benefit the Person Born as a Result?” is to argue that GGE would not be person-affecting; this is because, according to Sparrow, GGE would still involve selection of which embryos to transfer to initiate a pregnancy. According to a widespread assumed premise in this debate, selection of embryos is equivalent to a choice of which person, out of a set of possible persons, eventually comes to exist, and as such, it is identity-affecting. Sparrow sets his argument within the giant debate about potential use of GGE as a tool for enhancement. He justifies this briefly toward the beginning of the paper. My concern here is with one of Sparrow’s reasons for focusing on enhancement. Sparrow rejects the potential for GGE to be used as a therapeutic intervention; since “... the therapeutic case for germline genome editing is weak,” he assumes that GGE will “primarily be used for... enhancement.” This seems to back up a sentiment about GGE that is in the air— namely, that any talk about its use for therapeutic purposes is really a kind of normative Trojan Horse, to speed the acceptance of GGE for enhancement (and, indeed, Sparrow seems to endorse this idea, when he says therapeutic use of GGE “...undoubtedly has utility for garnering public support for genome editing”). Sparrow’s reasoning in favor of this rejection is— apologies for the blunt statement, but sometimes bluntness is called for—flat out wrong. I’m not going to argue here that Sparrow is wrong because GGE really does have therapeutic value; rather, I think it’s an open question, as of now, whether it could, and there is a significant philosophical problem about whether GGE has any therapeutic utility. To be fair, Sparrow does not give a fully developed argument that there is a “weak” case for therapeutic use of GGE; his brief statement in support of this assumption repeats three widespread claims in the literature on GGE. The first is that GGE offers no clinical benefit over and above existing assisted reproductive technologies (ARTs) for dealing with heritable genetic disorders; preimplantation genetic diagnosis (PGD) is an already available means to accomplish the same goal (of having a disease-free child). Second, in cases where PGD won’t work, gamete donation is also available. The third reason Sparrow offers needs to be cited au naturel: