"Natural" vs "Normal" with Gene Therapy/Enhancement
The National Academy of Sciences has published an extensive document on the ethics and governance of genome editing (see here). This is very timely for me as I am in the process of writing, and I hope completing in the next few months, a textbook on this general topic.
In the chapter dealing with genetic enhancement there is a brief discussion of the conflation of describing particular genetic mutations or constitutions as "natural" with the sentiment that they must therefore be "positive" and "beneficial". This conflation typically occurs when people object to genetic manipulation on the grounds that it is "playing god". The report helpfully explains the problem with this stance:
The word “natural” has similarly taken on a positive connotation reflecting a common view
that nature produces things that are healthier and generally better than anything artificial—this
despite evidence demonstrating that “natural” things can be either safe or intrinsically dangerous.
In the present context, genetic variants that exist in nature may either support health or cause
disease, and the human population contains multiple variants of most genes (see Chapter 4).
Thus, there is no single “normal” human genome sequence; rather, there are multiple variant
human genomic sequences (IGSR, 2016), all of which occur in the worldwide human gene pool
and, in that sense, are “natural,” and all of which can be either advantageous or disadvantageous. (p. 106)
Given evolution by natural selection has given us genes, and genomes, for both health and disease, the question is whether humans ought to purposefully intervene in the genetic lottery of life to bring about a more desirable outcome than that conferred by the arbitrary process of evolution by natural selection. As the prospect of successful human intervention increases, so too, I believe, does the moral imperative to intervene to improve our biology beyond the confines of what evolution by natural selection has provided.