Bridled enthusiasm

When it comes to the politics of embryonic stem cell technology, it seems that every word must be vetted, analyzed and then reanalyzed. The latest example is provided by what started out as an interesting scientific paper from Advanced Cell Technology Inc. The report, published online by Nature last Wednesday, was trumpeted in important newspapers the next day as a breakthrough in the argument over the research use of human embryos. But by week's end, Nature had felt compelled to issue two clarifications to keep the facts in perspective.

The paper from researchers at ACTC (Alameda, Calif.) described a series of 10 experiments showing that human embyonic stem (hES) cells can be derived from single blastomeres, the cells produced by division of the egg directly following fertilization. They reported that 19 ES cell-like outgrowths and two stable hES cell lines were obtained. ...