Sir

Appeals to human dignity, and to the moral obligation to protect it, have been a feature of responses to the cloning of Dolly the sheep ( Nature 385, 810–813; 1997). Dr Hiroshi Nakajima, director general of the World Health Organization (WHO), said: “WHO considers the use of cloning for the replication of human individuals to be ethically unacceptable as it would violate some of the basic principles which govern medically assisted procreation. These include respect for the dignity of the human being.”

The European Parliament rushed through a resolution banning cloning, which stated as part of the rationale (clause 6) that the parliament “believes it is essential to establish ethical standards, based on respect for human dignity, in the areas of biology, biotechnology and medicine”. Neither of these august authorities provided a scrap of argument as to how the idea of human dignity is relevant to the ethics of cloning.

A first question to ask when the idea of human dignity is invoked is: whose dignity is attacked and how? Is it the duplication of a large part of the genome that is supposed to constitute the attack on human dignity? If so, we might legitimately ask whether and how the dignity of a natural twin is threatened by the existence of the other twin. The notion of human dignity is often also linked to Kantian ethics. A typical example, and one that attempts to provide some basis for objections to cloning based on human dignity, is Axel Kahn's invocation of this principle in his Commentary on cloning (Nature 386, 119; 1997).

But the Kantian principle, which is generally interpreted as demanding that “an individual should never be thought of as a means but always also as an end”, crudely invoked, as it usually is, without any qualification or gloss, is seldom helpful in a medical or bioscience context. It would outlaw blood transfusions and abortions carried out to protect the life or health of the mother. It would also outlaw one form of cloning, embryo splitting, which could allow genetic and other screening by embryo biopsy. One embryo could be tested to ascertain the health and genetic status of the remaining clones, and then destroyed. To this it is objected, pace Kahn, that one twin would be destroyed for the sake of another.

It is bizarre and misleading to marshal the Kantian principle as an objection either to using cell mass division to create clones for screening purposes, or to creating clones by nuclear substitution to generate spare cell lines. It is surely ethically dubious to object to one embryo being killed for the sake of another, but not to object to it being killed for nothing. In in vitro fertilization (IVF), for example, it is, in the United Kingdom, regarded as good practice to store spare embryos for future use by the mother or for disposal at her direction, either to other women who require donor eggs, or for research, or simply to be destroyed. It cannot be morally worse to use an embryo to provide information about its sibling than to use it for more abstract research or simply to destroy it. If it is permissible to use early embryos for research or to destroy them, their use in genetic and other health testing is surely also permissible. The same would surely go for their use in creating cell lines for therapeutic purposes.

A moral principle that has at least as much intuitive force as that recommended by Kant is that it is better to do some good than to do no good. It cannot, from the ethical point of view, be better or more moral to waste human material that could be used for therapeutic purposes than to use it to do good. If it is right to use embryos for research or therapy then it is surely also right to produce them for such purposes, as is usual in IVF. Kant's prohibition does after all refer principally to use. Of course some will think that the embryo is a full member of the moral community with all the rights and protections possessed by Kant himself. Although this is a tenable position, it cannot consistently be held by any society that permits abortion, post-coital contraception or research with human embryos.