British researchers are reporting success creating human primordial germ cells (the precursors of egg and sperm) from embryonic stem cells.

Reuters has the story:

"We've shown we can generate primordial germ cells. These are the cells that go on to form either the sperm or the egg depending on the gender of the individual," said Professor Harry Moore, a reproductive biologist at the University of Sheffield in England.

"In culture, we've been able to show, using human embryonic stem cells, that some of those cells develop further to a later stage of sperm development," he told Reuters.

Possible cure for infertility? In addition to making babies, eggs are the raw material for making new embryonic stem cell lines. The application of this work to making eggs could eliminate the problems of limited egg donation. It also will raise issues for the anti-embryonic-stem cell position: do embryos made completely from in vitro grown cells still count as "human life"?