Researchers from the United States and France have succeeded in growing
mouse egg cells from both male and female embryonic stem cells in laboratory
cultures. The report was published online on May 2 on the Web site of Science (http://www.sciencemag.org) and in print
in the journal's May 23 issue.
Previous efforts to coax cultured embryonic stem cells to develop into
egg or sperm cells had been unsuccessful; the feat is the first demonstration
that mammalian embryonic stem cells remain totipotent, or capable of developing
into every cell type, even outside the body.
Stephenson J. Egging on Stem Cells. JAMA. 2003;289(22):2929. doi:10.1001/jama.289.22.2929-a