Fertility scientists have created human eggs using cells from the amniotic sac that surrounds a baby in the womb.
Experts believe the discovery will lead to routine manufacture of human eggs for infertile couples, avoiding the need to rely on egg donation from fertile women.
"Doctors have been looking for an alternative to egg donation for a long time. We hope it will soon be possible to grow as many eggs as needed," Professor Eliezer Shalev, of Technion Israel Institute of Technology in Haifa, northern Israel, who led the research, said.
Amniotic cells develop at the early stages of the life of the foetus and are known to be able to change into other cell types.
So far eggs grown from amniotic sac cells are immature, at the stage of germ cells found in the ovaries of girls before they reach puberty, the Daily Express reported.
Scientists have now started using hormone stimulating chemicals to develop these cells into mature eggs capable of fertilisation by sperm.
Shalev believes it may be possible to grow mature eggs in two to three years.
"We think that the vast majority of women would be more than happy to donate the amniotic sac, rather than it being thrown away," Shalev said.
Donor eggs have been available for more than 20 years but the process is fraught with problems and demand often outstrips supply.
The discovery has stirred controversy among some experts, who say there may be ethical concerns.
"There might be ethical issues. There could be an argument that the amniotic membranes belong to the baby they surrounded. This would have to be tested in court," said Professor Lawrence Shaw, a leading London fertility specialist.
The study was published in the journal Reproductive Biology and Endocrinology.