The European Patent Office said today it had added restrictions to a controversial patent granted in 1999 so that it could not be used to clone humans.
The Munich-based office said it had revised the patent it granted to Edinburgh University in 1999 on altering animal cells.
Edinburgh University and an Australian biotech firm Stem Cell Sciences were awarded the patent to genetically alter the cells of mammals, which could then be used to create embryos.
The European Patent Office acknowledged a few months after granting the patent that it had made a mistake in doing so.
However, rather than revise its decision immediately, the office had to wait for outside parties, including the governments of Germany, Italy and the Netherlands, to file motions expressing opposition to the patent.
The patent office said officials had not noticed a reference to human cells in the 235-page document.