European officials have closed a loophole in a research patent issued three years ago that could have permitted the cloning of human beings.
The dramatically revised patent issued yesterday rules out the harvesting of human or animal embryo stem cells and brings it in line with a European Commission directive that bans patents on the use of human embryos for commercial purposes.
The move came after formal complaints to the European Patent Office (EPO) from the governments of Germany, Italy and the Netherlands, as well as Greenpeace, following international outcry over the decision.
The Munich-based EPO issued Patent EP 695 351 to the Australian firm Stem Cell Sciences in December 1999 to allow the extraction of embryo cells for later genetic modification - a process based on research carried out at the University of Edinburgh in Scotland.
The revised patent now covers only research on adult stem cells from humans and animals which can be retrieved from body tissue in living organisms.
The EPO acknowledged three months after granting the initial patent that it had committed a "serious mistake" in theoretically allowing the genetic manipulation of human embryos. The patent-holders later formally agreed not to clone humans, saying it had never been their intention.
Scientists from the University of Edinburgh had defended the patent as allowing them to examine how human cells could develop in a laboratory, adding that this was accepted scientific practice. They said the research could provide breakthroughs in replacing damaged human cells, for example in patients with Parkinson's disease.
But environmentalists and political leaders said the EPO's decision had initially set a dangerous precedent and welcomed yesterday's ruling.
"We are completely satisfied with the decision," said Mr Christof Keussen, a patent attorney representing the German justice ministry at the EPO hearing.
He called the ruling a victory for bioethics that clearly barred the commercial use of embryos as well as human cloning.
Greenpeace spokesman Mr Christoph said it would now be more difficult for industry to push through patents involving cloning and said there was an ethical difference between research on stem cells for medical or commercial purposes.
He called for a clear legal distinction between the two and a general ban on any patents covering the genes of plants, animals or human beings.
Opponents of human cloning cite not only the ethical minefield it would create but also medical evidence showing the likelihood that a cloned child would die in infancy or be handicapped for life.
National governments have been moving to ban human cloning and set limits on stem cell research, but environmentalists have urged international co-ordination of bioethics measures.
The EPO is an independent authority controlled by an administrative council representing 20 member countries.