They then took unfertilized eggs and stripped the genetic material from them.

"And the majority of people who are asked are happy to give unfertilized eggs to the research."

If anything, the decision by the Newcastle group to use only unfertilized eggs may make their task more difficult.

For this reason, cryopreservation of unfertilized eggs is less effective.

They were particularly surprised that the researchers had managed to assemble so many unfertilized human eggs, 247 in all.

The academy also says that donors, including women who donate unfertilized eggs, should not be paid.

When a mother wasp wants to produce a male, she lays an unfertilized egg.

The new source is the unfertilized eggs that can be harvested from ovaries.

The women who provided unfertilized eggs that were needed to start the cloning process were not paid.