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Introduction

Our genes play an important role in what kind of people we are – whether we are, for example, short or tall, healthy or sick, mentally slow or bright; and while there is debate about the extent to which certain characteristics are inherited or the product of our environment, it is difficult to deny that some characteristics at least have a genetic basis. To deny this would, as Jonathan Glover points out in “Questions about Some Uses of Genetic Engineering” amount to thinking “that it is only living in kennels which makes dogs different from cats”.

Genetic manipulation, sometimes also referred to as genetic engineering, involves intervening at the genetic level in order to eliminate, modify, or enhance certain genetic traits or conditions. Recent scientific breakthroughs, including the mapping of the human genome, have added significantly to our understanding of our genes, and provide increasing and unprecedented possibilities for control over our genetic destiny. Should we make use of this knowledge, and to which ends? Should we, for example, use genetic manipulation only to prevent serious genetic disorders, or should we also use it for the enhancement of certain traits and characteristics?

The distinction between gene therapy and gene enhancement is not clear‐cut. While it might be agreed that increasing the height a boy is expected to reach at maturity from 170 cm to 190 cm is a form of enhancement, what if we are seeking to increase his expected height from 150 cm to 170 cm? The same appears to be true when we are looking at a trait such as intelligence. Increasing a person’s IQ by 20 points from 110 to 130 would generally be considered enhancement, but would raising her IQ from 90 to 110 be therapy or of enhancement? The answer ultimately depends, David B. Resnik argues in “The Moral Significance of the Therapy–Enhancement Distinction in Human Genetics,” on contested philosophical distinctions, such as the distinctions between health and disease, and normality and abnormality.

Despite some fuzziness at the margins, we do, however, often have a plausible understanding of where the boundary between therapy and enhancement should be drawn. The next question is whether this boundary is morally significant. Again, many people think the answer is “yes.” They take the view that gene therapy, as an extension of the conventional goals of medicine, is morally acceptable, while enhancement is morally problematic. But are the arguments in support of the ethical significance of these distinctions sound?

Some people reject positive genetic engineering on the grounds of risk; but is risk – even significant risk – a sufficient reason to rule out all genetic interventions? Jonathan Glover argues that the fact that a practice involves risks is not sufficient to show that it is morally wrong, or should be banned. In some cases, the dangers of not proceeding might be greater than the dangers of proceeding selectively and cautiously. Moreover, would considerations of risk be a reason against all positive interventions, or against only some of them? And would it be a reason against positive or enhancing genetic interventions only, or also a reason against therapeutic or negative interventions?

Arguments about risk are important, but do not go to the heart of the objections to genetic engineering. Even if gene therapy could be shown to be relatively safe, one oft‐heard objection – that it involves “playing God” – would remain. But this objection, as Glover and others argue, is unpersuasive. Taken literally, it obviously will not appeal to non‐believers; and, if understood metaphorically as a prohibition on interfering with “God’s creation,” that is, with nature, it would seem to rule out not only all genetic engineering (whether positive or negative), but all other medical interventions as well.

A more plausible way of understanding the “playing God” argument might be to see it as an objection to eugenic schemes, where, as Glover puts it, necessarily fallible people with limited horizons are making God‐like decisions to improve the human race. Past eugenic programs in Europe (and particularly in Nazi Germany), Great Britain, and the United States continue to cast a dark shadow over contemporary genetics. These programs were widely associated with a variety of often highly questionable coercive government schemes intended to “improve” the gene pool. The question of whether positive genetic engineering is morally acceptable must, however, Glover argues, be separated from the question of whether particular state‐controlled eugenic programs are acceptable. One might think that it is wrong for state authorities to decide who should and should not be able to have children, and what these children should be like, but not wrong if individual parents were to make these kinds of reproductive decision themselves.

Those who are most enthusiastic about genetic enhancement call themselves transhumanists to signify that they think it desirable to move beyond the human nature that we have inherited from the long and blind process of evolutionary selection. Nick Bostrom in “In Defense of Posthuman Dignity,” defends transhumanism against the criticism that if we change our nature, we will lose our human dignity. Though the idea of human dignity is often invoked, the values behind it are rarely made explicit. Bostrom distinguishes different things that we might mean by “human dignity.” He then defends, as the title of his essay indicates, “posthuman dignity” – that is the idea that there is moral worth in seeing human nature as dynamic and changing, and in seeking to make moral progress by improving it.

Francis S. Collins was appointed Director of the United States National Institutes of Health (NIH), one of the world’s largest public funders of biomedical research, in 2009. Prior to that, he directed the National Human Genome Research Institute, in which capacity he played a leading role in mapping and sequencing the human genome. In his “Statement on NIH Funding of Research Using Gene‐Editing Technologies in Human Embryos,” Collins defends NIH’s long‐standing policy against funding research involving the use of gene‐editing technologies in human embryos. As he points out, NIH also does not fund research proposals that alter genes in ways that may be passed on to future generations. Collins notes that some of this research is being done in China, and cites legislation and regulations that exclude the possibility of such research in the US.

Giulia Cavaliere’s “Genome Editing and Assisted Reproduction: Curing Embryos, Society or Prospective Parents?” focuses on whether genome editing might be preferable, for ethical reasons, to preimplantation genetic diagnosis (PGD), which is currently in use in several countries, including the United States. Cavaliere evaluates two sets of concerns about the use of genome editing on human embryos or gametes in a clinical setting: safety concerns and ethical objections to introducing changes into the human germline. In this context she cites, and gives reasons for rejecting, the position taken by Francis S. Collins in the statement included in Chapter 16 of this Anthology. She then discusses the potential benefits of genome editing, given that it would not be vulnerable to some of the ethical objections to PGD, and could be used in cases where PGD is ineffective.

Cavaliere cautions us to assess thoroughly the safety of genome editing, but she does not find compelling the claim that it is wrong to introduce any modification of the human germline. She argues, however, that societies need an ethical policy for allocating social resources so as to ensure equality of access to assisted reproduction, including assistance that which makes use of genome editing.

R. Alta Charo asks us in her article “Who is Afraid of the Big Bad (Germline Editing) Wolf?” to be wary of unsubstantiated claims about significant dangers associated with human germline editing. She argues that time and again in human history, when biomedical research offered society new technologies and possibilities, there have been dire warnings and predictions about their supposed risks. Among others she mentions the argument that germline editing could turn children into commodities. The same types of arguments were raised historically by opponents of the introduction of, for instance in vitro fertilization (IVF), surrogacy, and PGD. None of these worries turned out to be justified. Charo’s concern is that societies might give undue weight to such worries and unnecessarily impede research and the development of new means of reducing the social burden of disease.

In the short article that concludes this Part, Julian Savulescu and Peter Singer discuss a controversial example of gene editing involving two healthy embryos that were allowed to develop into children. He Jiankui, a Chinese biophysicist who has since been sentenced to jail for undertaking this work, claimed to have edited out a gene that produces a protein that permits HIV to enter cells. Savulescu and Singer argue that the experiment was unethical because the risk–benefit ratio did not justify subjecting the children to the currently unreasonable risks associated with human gene editing. They also raise concerns about likely flaws in the process of obtaining informed consent from the future parents of the embryos. But what if, in future, gene editing is possible without the risk of off‐target mutations? This paper indicates possible ethical pathways to human germline gene editing.