A recent research trend has targeted the goal of having one's stem cells and preserving embryos, too—a nod to powerful critics such as President George W. Bush. Even if an embryo remains intact—the objective of these studies—it is unclear whether these methods will ever satisfy Bush and others who rail against what they perceive as immoral tinkering with the stuff of life.

Kevin Eggan and his colleagues at the Harvard Stem Cell Institute brought together embryonic stem cells with skin cells, or fibroblasts, creating fusion cells that reprogrammed themselves to resemble embryonic stem cells genetically matched to the donor of the skin cell. These cells would have the versatility to turn into any other cell type—and would not require a cloning procedure that necessitates the destruction of an embryo.

The promise of stem cells was again reaffirmed by an experimental therapy to treat patients with lupus—a disease in which the patient's immune system targets the body's own tissue. A group led by Richard K. Burt of the Northwestern University, Feinberg School of Medicine, removed stem cells from the patient's bone marrow. Drugs then wiped out the population of white blood cells before the stem cells were returned to the body, where they formed new white blood cells that were less likely to make damaging antibodies. In a study of 48 patients, half did not have the disease after a period of five years.

Determining how an embryonic stem cell differentiates into mature cells might eventually allow development of methods to reprogram an adult cell. Those techniques might let the mature cell return to its pluripotent state, in which it is capable of turning into different cell types. Laurie A. Boyer and Richard A. Young of the Whitehead Institute for Biomedical Research and their colleagues demonstrated how three proteins control this process.

Another research finding highlighted the importance of exploring the complexities of stem cell biology without having to satisfy the demand for immediate medical benefits. Susan L. Lindquist of the Whitehead Institute and her collaborators demonstrated that the prion protein, which causes mad cow disease when malformed, has a critical stem cell–related function in the body in its normal state. The protein appears to help nurture and maintain the body's supply of stem cells that produce blood cells.

Bush's decision to limit stem cell research to 78 existing cell lines has hindered the field. Today far fewer cell lines are viable than the original number permitted, and many of them are contaminated. Representative Diana DeGette of Colorado, a Democrat, and Representative Mike Castle of Delaware, a Republican, have been trying to loosen restrictions. They have succeeded in getting support from their colleagues in Congress but were ultimately stymied by Bush's veto—the first of his administration. A commitment is needed to continue basic research on stem cells unfettered by political considerations.