"Embryonic stem cells without embryos? Could it really work?" George W. Bush's question was directed to me. It was May of 2005, and the president, vice president and half a dozen White House staffers—of whom I was easily the most junior—were gathered in the Oval Office. I was a member of the domestic-policy staff, and the briefing was on the state of the stem-cell debate, which fell in my portfolio.

Toward the end of the meeting, I gave Bush a copy of a report about to be published by his bioethics council, entitled "Alternative Sources of Pluripotent Stem Cells." The council (on which I had previously served as executive director) had been looking into obtaining the kind of valuable cells researchers derived through the destruction of embryos, but without requiring such destruction. If an alternative worked, it could offer a scientific way around the ethical dilemma at the heart of the embryonic-stem-cell debate.

The most ethically and scientifically appealing of the potential approaches the council's report raised was what it termed "somatic cell dedifferentiation": taking a mature, adult cell and turning it into the equivalent of an embryonic cell without the need for an embryo.

And in my conversations with scientists that spring, I discovered that work toward this approach was much further along than the council suggested. Again and again researchers said there was real promise there, and pointed to preliminary work at Harvard and in an Australian lab. So could it work? "The scientists seem to think it could, with time," I told the president, "but no one knows for certain."

In the months that followed, we did what we could to gather information and to help. Several researchers came to meet with the president, and we on his staff talked to many more. Bush also began to mention the subject in remarks on the stem-cell debate. And he sought to put funding where his mouth was. In 2007, he signed an executive order to increase support to such techniques.

All the while, against immense political pressure, Bush stood his ground on the basic moral conviction that because we are all created equal, nascent human lives should not be treated as raw material for experimentation. We could support medical research without crossing that line.

Stem-cell scientists needed no help seeing the enormous potential of somatic-cell reprogramming. It would offer them a much easier route to the promising experiments they were after, and could also remove barriers to federal funding and make their work less controversial. Almost none of them agreed with Bush's objections to the destruction of embryos for research, and his encouragement was not the reason they pursued the new technique. But his encouragement did show that success with alternatives to embryo destruction could bring wholehearted public support, and end the political drama over their work.

In November of 2007, that work reached a very public crescendo. Two teams announced they had successfully returned human skin cells to "an embryonic-like state" without the need for embryos. It was an astonishing feat, and came faster than anyone imagined possible. Since then several further refinements of this technique have been published.

These advances have sparked enormous excitement in the field. Researchers are quick to note it is too soon to be certain if the new cells created this way are identical to embryonic stem cells, and they would still prefer to explore all available avenues, since they see no ethical problem with destroying human embryos for research. But for those who do see a problem, and seek a balance between scientific and ethical concerns, the new approach has shifted the balance dramatically, and may in time spell the end of the stem-cell debate.

But politics does not always reflect reality, and even as the facts were changing, some kept clamoring for an end to the Bush policy. Earlier this month, they got their wish: President Obama overturned Bush's rules and for the first time permitted federal dollars to support research that relies on the ongoing destruction of embryos.

The real lesson of the stem-cell debate was not on display in the president's decision. That lesson, made evident through new alternative stem-cell techniques, is that precisely because science is flexible, ethics must be clear and firm. Given proper direction from the larger society, our scientists are up to the task of finding ways to advance research without crossing crucial moral boundaries. To avoid the choice between science and ethics, we should insist on ethical science, and see the task of self-government in an age of biotechnology, in Bush's words, "as a challenge to advance medicine while meeting our solemn obligation to defend human life."

That twofold challenge will weigh heavily on the politics of the coming decades, and it will not be easy to meet. But "could it really work?" Yes, with the right policies, and the right scientific techniques, it could.

-- Levin is the Hertog Fellow at the Ethics and Public Policy Center and author, most recently, of Imagining the Future: Science and American Democracy.