Professor Ian Wilmut of the Roslin Institute in Edinburgh, who gained fame for cloning Dolly the sheep, has applied for a license to clone human embryos so he can study motor neurone disease.
His application to the Human Fertilization and Embryology Authority is expected to provoke criticism that testing human embryos is immoral.
Wilmut's team plans to take DNA from the skin or blood of a person with the disease and implant it into a human egg from which the genetic material has been removed.
The egg would then be stimulated to develop into an embryo.
Scientists would remove cells from the embryo while it was still in the earliest stages of development and study them to gain a greater understanding of the disease. The embryo would be destroyed while still just a few days old, Wilmut said.