President Bush’s Aug. 9 address to the nation on federal funding for embryonic stem cell research was a thoughtful presentation on the scientific and ethical concerns in play, and his decision to fund research only on existing stem cell colonies effectively balanced those concerns. It was clear, however, that the decision was merely a first step and that the entire issue would, sooner or later, need revisiting.

It now appears that revisiting will come sooner. Mr. Bush’s decision was based upon his assertion that the 60 or so existing stem cell colonies were more than enough to get this vital research under way, to allow scientists to explore this avenue as they simultaneously explore the use of stem cells derived from adults. That number is now in question and with it the president’s assertion.

From the start, many scientists doubted that the number of useful and available stem cell colonies was even close to 60. These cells, extracted from 5-day-old embryos, are exceedingly fragile and often short-lived. Many of the colonies are owned by private-sector laboratories; those labs have been filing dozens of patent applications covering all aspects of stem cell research and the potentially lucrative discoveries that may result, a situation that should be unacceptable to universities and other publicly funded research institutions. And now, to add to the scientific, ethical and commercial complications, a towering legal obstacle – some of these private labs may not have obtained adequate informed consent from the embryo donors, primarily couples using fertility clinics.

So now the doubt has spread from many scientists to most scientists. The American Association for the Advancement of Science – at 138,000 members, the world’s largest group of scientists – released a statement during the weekend saying that until much more is known about source and viability of the colonies, it will be impossible to assess their potential value for research. Many in Congress also are skeptical and have asked the Department of Health and Human Services to answer specific questions regarding the potential obstacles – access, availability, quality and legal status – to researchers.

That department, and other administration officials, say they have been unable to release such data because much of it is proprietary information controlled by the private labs that own the colonies. In fact, DHHS cannot even obtain information about the ethnic origin of the 60 cell colonies, vitally important information since the therapeutic value of stem cells is greatest among closely related ethnic and racial groups. What is known is that many of the colonies were created in Asia – just one company in Singapore owns six, or 10 percent of the total – which would limit their usefulness in treating people of European or African ancestry.

The president’s speech of two weeks ago was a political success, shifting the focus from an argument over whether there would be federally funded research to an outline of how American taxpayers can participate in the curing of such devastating diseases as Alzheimer’s, Parkinson’s, multiple sclerosis and diabetes. If the president was authorizing research that cannot be conducted, especially if it is found that the administration intentionally inflated the number of existing colonies, it was a success Mr. Bush bought at the price of his credibility.