Alternative sources of pluripotent stem cells: scientific solutions to an ethical dilemma.

Stem cell researchers in the United States have faced a quagmire of uncertainty due to multiple factors: the ethical divide over the use of embryos for research, the lack of clarity in federal guidelines governing this research, the restrictive patent situation surrounding the generation of new human embryonic stem (HES) cell lines; and the limits on types of research eligible for federal funding. In this commentary, we describe how recent advances in derivation of hES cell-like lines may allow at least some of these uncertainties to be resolved. More importantly, we suggest that the derivation of hES cell-like lines by morally acceptable methods would not only avoid the corrosive effects of a protracted ethical debate over stem cell research, but would also allow U.S. researchers to access federal funds and compete on a more level international playing field.