Washington ? Scientists in Massachusetts said Thursday they had created several colonies of human embryonic stem cells without harming the embryos from which they were derived, the latest in a series of recent advances that could speed development of stem cell-based treatments for a variety of diseases.

The new work shows for the first time that healthy, normal embryonic stem cells can be cultivated directly from embryos without destroying them.

That means the work should be eligible for federal financing under President Bush’s six-year-old policy of funding only stem cell research that does not harm embryos, said study leader Robert Lanza, chief scientific officer at Advanced Cell Technology in Worcester, Mass.

But that is not likely, said Story Landis, who heads the National Institutes of Health stem cell task force.

The embryos Lanza used, which were donated for research, appear not to have been damaged, Landis acknowledged. However, she said, “it is impossible to know definitively” that the embryos were not in some subtle way harmed. And “no harm” is the basis of the Bush policy, she said.

Landis said the only way to prove that the technique does not harm embryos would be to transfer them to women’s wombs and see if the resulting babies were normal. But it would be unethical to do that experiment, she said, so the question cannot be answered.