Paul Vallely: I am excited, but deeply worried, about human cloning

'We are uneasy that there may be a violation of something sacred going on here'

There are a handful of clear-sighted individuals, or shall we call them zealots, who have no doubts about cloning. They stand on both sides of the debate. There are those who greeted the news that an American team has succeeded in cloning a human embryo with unalloyed joy. It is only a matter of time before scientists using the stem cells derived from such embryos will come up with ways to make skin for burns victims, brain cells for those suffering from Parkinson's, and tissue to help with the scarring caused by heart attacks.

Then, on the slippery slope side of the argument, there are those who say that even therapeutic cloning is a step too far. There is no evidence that cloning can provide a cure for any disease, only a vague aspiration to find such cures. Moreover, if cloning worked, it would do so by deliberately creating and then destroying new human lives – which is tantamount to creating a class of people who don't have the same human rights as others. And the techniques developed will inevitably lead to the birth of the first cloned baby.

Many of us don't entirely buy either of these arguments. We find ourselves simultaneously excited by the prospect of a miraculous scientific breakthrough and yet uneasy that there may be a violation of something sacred going on. Not for nothing does the story of Dr Frankenstein linger in our modern mythology – and the detail that the recipient cell and the donor DNA were triggered by a charge of electricity in this first cloned embryo only feeds on the Hollywood imagery.

The scientific and religious zealots both dislike such thinking. It mixes together a dangerous cocktail of intuition and reason, instinct and scepticism, sacred and profane, all of which sit awkwardly with the revealed truths of either certainty. There are those who argue that the history of humankind has been a progress from the one to the other – an irreversible "shift to rationalisation", as Max Weber called it. As scientific rationalism increasingly dominates our way of thinking, so the power of ancient taboos and intuitions has withered.

As, in many cases, it has. The ancient world was filled with dread that supernaturally caused danger would be visited upon men and women if they infringed certain rules that were undefined, or at least unexplained, and deeply feared. Certain animals were unclean. Things from the house of a dead man were tainted. At the approach of a menstruating woman, as the Roman Pliny recorded, "wine will become sour, seeds touched by her will become sterile, grafts wither away, garden plants are parched up and the fruit will fall from the tree beneath which she sits".

The modern world may scoff at such notions, which persist still in some Hindu, Jewish, Christian and Muslim societies. But there is an element of taboo in much of the continuing hostility directed towards homosexuality in Western societies. And although scientific or philosophical cases can be made for the prohibitions on incest and murder that are common to most societies – though not all societies define them in the same way – the general antipathy to them is largely instinctual. So it is with the idea that one person's genes can be reproduced over and over again through cloning.

The tricky question is: how do we determine whether our extant taboos are irrational relics or common sense? There are many blind alleys we need to avoid. One is the way that our morality is routinely affected by what we can't see. Just as geographical distance vitiates our sense of moral indignation, so, too, we should suspect, does the virtual invisibility of the embryo – "such tiny dots, yet they held such immense promise", in the unintentionally ambiguous words of one of the scientists responsible for this week's first cloning.

When it comes to the question of reproductive cloning, science itself offers sufficient warning. The vast majority of the 5,000 pregnancies involving animal clones have gone very badly. Most spontaneously abort; it took 246 unsuccessful clones to produce Dolly the sheep. Where clones are born they have malfunctioning livers, abnormal blood vessels, under-developed lungs, diabetes and immune system deficiencies. We must not, as the Chief Rabbi put it yesterday, play a similar Russian roulette with a child's life.

On therapeutic cloning most people feel less certain, but still uncomfortable. We are not sure when an embryo becomes a person, and so are prepared, albeit uneasily, to tolerate research in the first 14 days before the nerve cells appear. The trouble with the emergency legislation the Government is introducing this week to ban the implantation of a human embryo in a woman's womb is that it will not outlaw research on embryos after that vital day. With scientists like the Italian fertility doctor Severino Antinori talking about creating cloned embryos in Britain and exporting them for implantation, that discomfort can only grow. The Government will have to do a lot more to allay it.

p.vallely@independent.co.uk