In a paper published online yesterday in Stem Cells, the researchers report that they succeeded in generating pluripotent human ES cell lines--i.e., cells that can develop into many different kinds of cells-- from one of the 13 late-arrested embryos. To ascertain that they had stopped growing permanently, the scientists waited up to 2 days after the last cell division before trying to cultivate them. They then plated the embryos on a growth medium. Five of the 13 cultures generated outgrowths. And of these, two developed cells with ES cell characteristics. One of these was cultivated into a "fully characterized" human ES cell line, proving that it could differentiate into all three germ layers both in the dish and in live mice. The earlier-arrested embryos did not produce ES cell lines.On the one hand, this seems like a decent compromise. They only use embryos that had ceased to divide, meaning that potentially viable embryos are spared the treatment.
On the other, there's a whole host of other concerns. There's always the fear that scientists or doctors will simply make embryos wholesale to be used for research. Alternatively, researchers might artificially "arrest" the development of the embryos to make them qualify for research. And for people who find IVF morally untenable, this is just another unfit solution.
If this is the best compromise we can get on ESCR, then I suppose I'll take it. The biggest issue will be regulating the harvesting. Time, and more research, will show the potential of this new development.