One day we may accept the unthinkable, and humans will be cloned

The sensitivity of the subject is such that some in the medical community were wary of discussing it, arguing that further attention would only inflame opinion, and could thus do no good. But the issue of reproductive cloning cannot simply be put to one side. The responses to The Independent's questionnaire to scientists about human cloning make it clear that this is an issue that cannot be brushed under the carpet. The problems will only grow in importance in the years to come. We must be able to address the subject coolly and rationally in order to decide what to do next.

The sensitivity of the subject is such that some in the medical community were wary of discussing it, arguing that further attention would only inflame opinion, and could thus do no good. But the issue of reproductive cloning cannot simply be put to one side. The responses to The Independent's questionnaire to scientists about human cloning make it clear that this is an issue that cannot be brushed under the carpet. The problems will only grow in importance in the years to come. We must be able to address the subject coolly and rationally in order to decide what to do next.

The results of the questionnaire reveal an interesting half-paradox. The great majority of the scientists polled cannot imagine circumstances in which human reproductive cloning would be justified. At the same time, the majority believes a shift in social attitudes is inevitable, and that (if the technical and safety issues can be addressed) reproductive cloning will be attempted within the next 20 years.

Already, stem-cell reproduction can be used for therapeutic cloning: stem-cell research will be enormously important in developing new treatments for disease. This deserves support. Opponents of therapeutic cloning are right, however, to note the "slippery slope" that lies between therapeutic and reproductive cloning. Once the first has come to seem normal, then the still-unthinkable may come to seem acceptable.

Many of us still find ourselves thinking along the lines of the nightmare scenario in Boys from Brazil. Multiply a little bit of Hitler 100 times and what do you get? A hundred little Hitlers. In our saner moments, we know, of course, that it is not true. Identical genes do not mean identical people. Even Siamese twins do not necessarily turn out the same. Chang and Eng Bunker, two joined-together brothers who gave the phrase "Siamese twins" to the world, both got married, and died in 1874 at the age of 63 - but were, by all accounts, very different personalities, despite the fact that they shared every single experience, from the womb until death. Anybody who has ever met identical twins - genetic duplicates - knows that they turn out to be very different people. In short, if Adolf had had a twin brother, there is no reason to suppose that he would have grown up to be a genocidal dictator.

Still, however, we are understandably wary of what reproductive cloning may mean. Even for the non-religious, the idea of seeking to predetermine an individual destiny ("this child shall have blue eyes, blonde hair and be a champion athlete") is somewhere on a continuum between distasteful and horrifying. It is essential that tightly framed laws remain in place to ensure that would-be engineers of the soul do not become all-powerful. Equally, however, it is clear that we may gradually find ourselves having to confront the currently unthinkable. Organ transplants, test-tube babies and surrogate babies all seemed horrifying when they were first mooted. In past decades, however, we have gradually - and with all due caution - come to accept them.

In due course, the same may be true of human cloning. It is right that the scientists remain mostly cautious, not gung-ho. But they are realistic, too. For the next generation, it is conceivable that reproductive cloning will seem almost as normal as the once-shocking heart transplants seem to us today.