The British government on Tuesday gave a human cloning license to the creator of Dolly the Sheep for medical research.
Britain was the first country to legalise research cloning in 2001.
The Human Fertilization and Embryology Authority, which regulates such research, approved the license for Ian Wilmut.
This is only the second such licence to be issued in the UK.
A team of researchers at Newcastle University was granted the first such license last August. The team hopes to employ cloning to create insulin-producing cells that could be transplanted into diabetics.
Wilmut, who led the team that created Dolly at Scotland's Roslin Institute in 1996, applied in September to Britain's fertility authority for a human cloning license. He wanted to study how the nerve cells are affected, causing motor neuron disease.
Abortion foes and other biological conservatives oppose such work, called `therapeutic cloning' because it does not result in a baby, as researchers must destroy human embryos to harvest the cells.
Wilmut and Christopher Shaw, a motor neuron expert of the Institute of Psychiatry in London, plan to clone cells from patients with the incurable muscle-wasting disease. They would then derive blank-slate stem cells from the cloned embryo, and allow them to develop into nerve cells. This would then be compared with nerve cells derived from healthy embryos.
The mechanism behind motor neuron disease is poorly understood because researchers cannot access the nerves in the brain and central nervous system and also cannot be removed from the patients.