In the view of some, the technique of extracting eggs from one woman, fertilizing them and implanting them in another is a miracle, enabling barren women to bear children.

They mature in the oviduct and so far it has proved impossible to extract eggs from a dog's ovary and mature them in the laboratory.

Dr. Lanza said cows were used as egg donors and surrogate mothers because there are so few gaurs left that it would be unethical to round up wild female gaurs and subject them to the treatments needed to extract eggs and implant embryos.

The graduate student had obtained cow ovaries from a slaughterhouse and was trying to extract eggs from them.

A team of about 15 people worked for nearly three years to extract eggs and implant more than 1,000 cloned canine embryos in surrogate mother dogs.

Some view the technique of extracting eggs from one woman, fertilizing them and implanting them in another, as a miracle.

Those included skilled technicians and a bountiful supply of human eggs - as many as 2,061 eggs from 129 women, an extraordinary number, given the pain and difficulty of extracting eggs from their donors.

The guy's promises of more to come had made it seem worthwhile to explore the idea, and a few phone calls led to a young researcher who'd been working on surgically extracting eggs from an ovary.

Women are being used as the raw material for such research because there is an invasive procedure to extract eggs, the raw material for cloning.