By transferring the pronuclei of a fertilized egg into the unfertilized egg of another woman, scientists hope to avoid passing on certain genetic defects.

Scientists from Britain's Newcastle University plan to transfer the pro-nuclei -- the components of a nucleus of a human embryo -- by a man and woman into an unfertilized egg from another woman to prevent mothers passing certain genetic diseases to their unborn babies.

'Necessary and Desirable'

The application was initially rejected because of legislation prohibiting the alteration of the genetic structure of a cell while it is forming part of an embryo, the Human Fertilization and Embryology Authority said in a statement. The authority is a government body that regulates fertility treatment and research.

The scientists eventually were given permission after reviewing the legislation.

"Having satisfied itself that the research activities were necessary and desirable under the criteria in the Human Fertilization and Embryology Act and that the use of embryos was necessary for the research, the committee ruled that a license for this research should be granted," the Fertilization and Embryology Authority said Thursday.

The research could eventually lead to techniques that might prevent the transmission of genetic defects, researchers say.

Mitochondrial Diseases

"While the proposed technique has been found to be safe in animal embryos, it will be very important to determine whether it can safely be used in human eggs," said university spokesman Mick Warwicker.

No treatment currently exists for mitochondrial diseases, which arise from DNA outside the nucleus and are inherited separately from DNA in the nucleus.

The research does not involve human cloning. It would use normal IVF procedures, but before the sperm and egg fused, components would be implanted into a healthy female egg.