We don't know if that will ever be possible. Without trying it, we can't know. But it is not what is generally meant by cloning, any more than my spit is a human being. Opposition to the research programme arises from a mixture of instinctive revulsion and religious, largely Christian objections. I don't disparage the yuck factor: often we can see that something is wrong long before we can explain why it is wrong; but the insight is not enough on its own: sooner or later we must give reasons for our revulsion, and this is where the trouble comes.
The basis of the yuck factor is an instinctive feeling that some things should not be done to human bodies. The trouble is that what is permissible to human bodies has varied wildly through time and round the world. Transplant surgery is still controversial in the Islamic world: it's nasty, but probably true, to say that it is less widely accepted than female circumcision. The use of dead people's corneas in transplants was illegal even in this country until the 1950s.
The yuck factor has led to the rejection of good things and the toleration of evil in every society but our own. With a little imagination we can realise that even our own might not be perfect. We need principles that are at least partly independent of our instincts to be able to judge what we should do; and this, I think, is where the Churches have noisily failed. Their speciality is the marriage of reason and insight, yet in their reasoning on this subject, the noisiest churches have managed to stress all the wrong insights.
The weakest part of the Christian case against embryo research and cloning is the assertion that a fertilised egg is a human being. So far as one can give any clear meaning to the term "human being", this is simply ridiculous. It's not just that we can do things an embryo can't. It has capabilities which even foetuses lose as they develop and differentiate. You can take a fertilised embryo, divide it into two clumps of cells, and each half will grow into a complete baby. Try doing that with a child, and see if you get two adults.
What seems even more unlikely: you can, with sufficiently early embryos, break them up as before, recombine the bits from two separate ones, and again, a complete organism results. That doesn't work with babies either. All these things are prime candidates for the yuck factor, but nature itself is yucky: it is reasonably common for early embryos to be reabsorbed by the lining of the mother's womb. We don't call that cannibalism.
By the same token, we should not regard the disposal of frozen embryos as murder. They are not human beings. They are not really animals of any sort and it is their extraordinary ability to generate and regenerate cells which makes the tissue so potentially valuable.
The more we know about the way that nature actually works, the less likely we are to confuse what is natural with what is ethical. The great unexamined premise of the yuck factor is that what is natural is good. But all that we can actually be sure of, in a Darwinian world, is that what is natural, frequent and works to our benefit, is unlikely to repel us very deeply. Cloned embryonic tissue sounds repulsive but is not; cloned children can sound more attractive, but their creation would be wrong.
I distrust the argument, though I have used it myself, that we should not be worried about artificial human clones, since natural ones - identical twins - already live quite happily. I think, at the very least, that they should be asked whether they consider their condition desirable before we make more of them. This won't happen, of course, because if human cloning does prove possible, it will be done by rich and powerful families who've never really worried about the effects of their dynastic needs on other people, even their own children.
Any discussion of what is natural or unnatural about reproductive technology ought to start from the fact that there is nothing new or unnatural about exploitation and the abuse of the powerless. There have been eunuchs for almost as long as there have been slaves; even the popes had a choir of castrati until 1878. I don't myself believe, as Catholics do, that the embryo or even the foetus is a human being. But they are surely right to start from a deep distrust of human nature.
Something of this distrust lies behind the British attempt to eliminate financial considerations from the research. But money functions both as a way to exercise power and as an information system. Prices show what people want. Outside Britain, big money will be on offer, and it will be accepted. This is tragic because cloning is not an offence against the embryo: it is an offence against the human being that embryo will become, not least because the qualities that people will clone for will be competitive.
The parents will buy, or try to buy, excellence in particular fields. They will want Einstein's brain, or even Bill Gates's. But just because they all want the best in a competitive field, it follows most must fail even when the technology succeeds. In Wimbledon fortnight we can see quite clearly what it does to a child to be groomed for one thing from the age of six; and those we see are the successful ones. Behind them are a legion of failures: thousands of teenagers who have worked just as hard with almost as much talent and got nowhere. It's bad enough to be ranked at 1,001th in the world after 10 years of effort. Imagine what that ranking would be like for a child who had been conceived, as well as trained, to be number one.
Cloning embryos to make stem cells is right because they're not human beings; cloning embryos to make babies is wrong because they will inevitably grow up to be unhappy human beings.