Sir

I welcome Lee Silver's call in his Words essay “What are clones?” (Nature 412, 21; 2001) for an informed public debate on human reproductive cloning, but I question his proposed basis for the discussion. Silver concludes that a person produced by nuclear transfer would be “a unique and unpredictable child who had the same DNA sequence as someone else, but nothing more”.

I disagree with his implication that a clone would necessarily have the same opportunity for individual development as a child produced by sexual reproduction. The reasons most commonly suggested for producing a clone are to overcome infertility or to replace a dead child. In the first case, the clone would be produced from one of the parents; in the second it would be from a child lost in an accident or after illness. The clone would be physically very similar to the original and have quite a similar personality, because of their shared inheritance. There would be greater similarity to the original in both regards than to any other person except an identical twin born at the same time as the original.

It seems inevitable that this unusual similarity and the reasons for the production of the clone would influence relationships formed by the child throughout its lifetime. If the original was a dead child in the same family, there is no doubt that the parents wish “to use cloning to bring dead children back to life”, as noted by Silver. What then would be the effect — not only on parents, but also on relatives, friends, school teachers and other children — of expectations that the clone would grow up like the original? If a parent were the original, would they have unusual and unreasonable expectations as to how the clone should develop? As the parent aged, how would the cloned child then react to seeing its physical future?

It is concern over these issues that makes me and many others reject the suggestion of cloning a person. The views of those who have studied child development would be very welcome.