Proving the effectiveness of embryonic stem cells requires time and research, as Californians who voted in support of Proposition 71 in November recognize. However, their efforts now appear fruitless with the recent discovery that all stem cell lines available for study are contaminated.

While there is no question that this disturbing discovery — made by UCSD School of Medicine and Salk Institute scientists — will cause much rethinking and many setbacks in future research, it does not mean that all stem cell work has to stop.

Continuing research should not be a question of morality, as critics like the Coalition of Americans for Research Ethics are trying to frame it, but rather one of consistency.

If there was a certain level of federal funding and local support for stem cell research before the discovery of contaminants, there should be that same degree of support now.

President George W. Bush should lift restrictions on federal funding for stem cell research and expand his policy — if not reverse it completely — to allow the study of at least some existing, conceivably uncontaminated lines that fertility clinics would otherwise toss.