An anonymous reader quotes a report from the BBC: Human eggs have been grown in the laboratory for the first time, say researchers at the University of Edinburgh. The team say the technique could lead to new ways of preserving the fertility of children having cancer treatment. It is also an opportunity to explore how human eggs develop, much of which remains a mystery to science. Experts said it was an exciting breakthrough, but more work was needed before it could be used clinically. Women are born with immature eggs in their ovaries that can develop fully only after puberty. It has taken decades of work, but scientists can now grow eggs to maturity outside of the ovary. It requires carefully controlling laboratory conditions including oxygen levels, hormones, proteins that simulate growth and the medium in which the eggs are cultured. But while the scientists have shown it is possible, the approach published in the journal Molecular Human Reproduction still needs refinement. In the paper, the researchers describe "how they took ovarian tissue from 10 women in their late twenties and thirties and, over four steps involving different cocktails of nutrients, encouraged the eggs to develop from their earliest form to maturity," reports The Guardian. "Of the 48 eggs that reached the penultimate step of the process, nine reached full maturity."