Epigenetics, Harm, and Identity.

Robert Sparrow (2022) argues that genome editing is unlikely to be person-affecting for the foreseeable future and, as a result, will neither benefit nor harm edited individuals. We regard Sparrow’s claim as being plausible—up to a certain point. However, Sparrow overlooks the role of epigenetics when it comes to determining our identity. Gene editing, as Sparrow suggests, would likely involve complex intervention, either at the gamete stage, or at the blastocyst stage. Since gene editing may result in “mosaicism,” where the amended genes are only active in a subset of the embryo’s cells, anything that focuses on one individual embryo would be fraught with uncertainty. It is currently very difficult if not impossible to control and predict the degree to which the change will permeate the organism. Also, in practice, in order to check the accuracy of the editing, genome editing will involve creation of, and selection from amongst, multiple embryos. These are some of the reasons Sparrow suggests genome editing is unlikely to be person-affecting. In all these regards, we suggest that his argument is compelling. Nevertheless, in his treatment of identity and the way it relates to questions about gene editing, the picture is considerably more complex than even Sparrow recognizes. Environmental factors, including our own behavior, and the behavior of our parents, can cause changes that affect the way our genes work (Hens 2017). If genes are an important aspect of our identity, epigenetic changes, as they are called, are also important; perhaps even more so, since they determine which of our genes are actually expressed. Therefore, epigenetics must also be taken into account when considering whether certain medical interventions harm or benefit specific individuals. Since Parfit (1984) wrote about the nonidentity problem, it has been widely accepted by many bioethicists that the essence of identity lies in the genes of the resulting offspring. It is this that makes it true that when Jane chooses to postpone having her child until she is cured of syphilis, she does not benefit that child, but gives birth to a different child. The egg and sperm that create the offspring are different in each case, therefore the child is genetically distinct from whatever child Jane might have had if she hadn’t waited. If identity is, as is commonly held, essentially connected with genes, then any intervention that alters genes raises the question of identity. Sparrow claims that bioethicists have assumed that genetic intervention would be person-affecting (rather than identity changing). Yet it seems strange that this should be the case. After all, if our focus is on genes, it would seem to follow that altering those genes does in fact change the identity of the organism. Thus, there can be no therapeutic genetic intervention, whether one is an adult, child, embryo or gamete. However, perhaps it is a question of degree: altering a few base pairs might not be identity changing, while swapping out a whole 23 chromosome’s worth of sperm contribution might be deemed too much. Intuitively there may be some appeal in this approach, but it does very little actually to resolve the question. This is because—if there is some threshold beyond which one becomes literally a new genetic person—the next challenge would be to establish, sensibly, where that threshold is. It seems very hard to know even where to start