ONE of the obstacles to human cloning has been cleared by scientists who successfully used skin to generate embryonic stem cells.
The advance, hailed as a “milestone”, is expected to aid the development of stem cell therapies that avoid fertilised human embryos, but since it employs a cloning technique it is certain to fuel controversy.
The scientists from the United States said they were not interested in cloning humans and did not believe their methods could successfully be used in this way.
But the therapeutic cloning technique they employed would also be the start of the process of making duplicate humans.
It is the first time scientists have managed to create human embryos through cloning developed enough to provide stem cells.
The same technique was employed by researchers at the Roslin Institute in Edinburgh to produce Dolly the Sheep, the first mammal to be cloned from an adult cell.
In the new study, reported in the journal Cell, scientists generated early embryos consisting of a cluster of 150 cells, from which human embryonic stem cells were obtained and grown in the laboratory.
Lead researcher Professor Shoukhrat Mitalipov, from Oregon Health and Science University, said: “Our finding offers new ways of generating stem cells for patients with dysfunctional or damaged tissues and organs.
“Such stem cells can regenerate and replace those damaged cells and tissues and alleviate diseases that affect millions of people.”
Prof Mitalipov added: “While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine.”
Human embryonic stem cells are normally derived from “unwanted” fertilised human embryos left over from IVF treatment, which raises ethical concerns.
He said there was a distinction between therapeutic cloning, the technique used in his research, and reproductive cloning and doubted that the same method could be used to clone human babies.
Prof Mitalipov said: “Our research is directed toward generating stem cells for use in future treatments to combat disease.”
Prof Robin Lovell-Badge, head of developmental genetics at the MRC National Institute for Medical Research, said: “This interesting work at last brings the topic of therapeutic cloning in humans back into the realm of good science rather than controversy.
“Many years of experience with reproductive cloning in animals tells us that the vast majority of cloned embryos fail at some point during gestation, most early after implantation, but all the way up to birth and beyond.
“It is an unsafe procedure in animals and it will similarly be an unsafe procedure in humans. For this reason alone, it should not be attempted.”
But anti-cloning campaigner David King, director of Human Genetics Alert, said the research opened the door to cloning human babies and branded it “irresponsible”.
He said: “Scientists have finally delivered the baby that would-be human cloners have been waiting for: a method for reliably creating cloned human embryos.
“This makes it imperative that we create an international legal ban on human cloning before any more research like this takes place.
“The main argument, that since it has been impossible to create cloned monkeys, the same will apply to humans is pure conjecture. Critically, with monkeys there are no hordes of desperate or egoistic rich patients and unscrupulous IVF doctors eager for fame and fortune to drive cloning efforts forward.”