Steve Connor: Technical barriers to human cloning can evaporate overnight

Perhaps the most important question raised by the latest study into primate cloning is whether this brings us any nearer to the prospect of a cloned human baby. Many scientists would say "no" on the grounds that this is not the intention of the researchers involved, and in any case such activity is illegal. I believe they are wrong.

The technology of somatic cell nuclear transfer – cloning of an adult – is difficult. In 1996, it took 277 attempts to create Dolly the sheep, and the success rate is still far too low to make it as simple as, say, in-vitro fertilisation.

Primates – including humans – posed even greater problems than many other species. No matter how hard scientists around the world tried, they were unable to clone a monkey offspring from an adult animal. Meanwhile, attempts on human eggs were mired in scientific misconduct. It has even been suggested that there may be some inherent barrier to Dolly-style cloning for all primates. However, the latest research coming out of Oregon suggests that the barrier was due to a flawed laboratory technique rather than a fundamental biological block.

Although the Oregon scientists have not yet succeeded in producing a cloned offspring, they have managed to produce dozens of cloned embryos, and some of them have developed well enough to generate stem cells – the mother cells of the body from which all specialised tissues derive. The technique will no doubt be studied by those scientists interested in producing cloned human embryos for the same purposes.

And if it is possible to improve the efficiency at which an unfertilised human egg can be merged with an adult's skin cell, then that too would be useful for anyone contemplating reproductive cloning.

Reproductive cloning is banned in about 50 countries in the world, which means that it is still legal in the majority of nations. Attempts by the UN to formulate an international ban ground to a halt a couple of years ago because some countries wanted a total ban on all types of cloning – such as therapeutic cloning – which Britain and other nations opposed.

In a report today, the United Nations University calls for a new global consensus to outlaw reproductive cloning so that there can be no place in the world where it could be undertaken legally. The problem we all face is that science is not static and apparent technical barriers to human cloning can evaporate overnight. If the cloning of human embryos becomes straightforward and reliable, then someone, somewhere will attempt to transplant a cloned embryo into the womb of woman. We may not be able to stop such a chilling development.