What a Bush Veto Would Mean for Stem Cells

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All this progress, however, does not yet mean that the demand for embryonic cells will disappear. Most adult organs just don't have enough stem cells to deploy as treatment, and adult stem cells are even harder to grow than embryonic ones. One goal of research is to help scientists understand how embryonic cells duplicate themselves perpetually. When it divides, a stem cell will occasionally create two different daughter cells, one that will continue to develop like any other cell and another that retains the ability to continue dividing indefinitely, thereby giving the cell line its immortality. "Unlocking the secrets of self-renewal will most likely involve studying embryonic stem cells," Kriegstein says. "And by understanding better how they work, we might be able to use that information to actually engineer adult stem cells to do the same thing." Then the discussion over how to handle an embryo could move into another phase, and maybe even leave the politics behind.

For continuing coverage of the President's stem-cell decision, go to time.com