The prospect of using a patient's skin to generate healthy heart, liver or nerve cells for transplant operations has moved a step closer after a scientists' breakthrough.
Using the cloning technique which produced Dolly the sheep in 1996, researchers for the first time turned human skin cells into "embryonic" stem cells, which can grow into any type of tissue in the body.
The discovery reopened an ethical debate about "reproductive cloning" yesterday, with critics claiming the "irresponsible" technology opened the door to the cloning of human babies.
But researchers insisted the technique, which involves the creation and destruction of early-stage embryos, is intended solely to lead to new treatments for disease and injury.
Dr Shoukhrat Mitalipov, who led the study at Oregon Health & Science University, said human cloning "is not our focus, nor do we believe our findings might be used by others to advance the possibility".
