On Wednesday, President Bush is prepared to veto stem cell research legislation, the second time he has used the veto pen for that purpose.

A Rasmussen Reports survey conducted earlier this year found that 66% of Americans believe that “embryonic stem cell research" is at least somewhat likely to lead to cures to previously incurable diseases. This figure includes 72% of Democrats, 59% of Republicans, and 69% of those not affiliated with either major political party. Americans under 30 were a bit more optimistic than their elders about the potential of such research.

However, 30% of Americans believe that embryonic stem cell research is morally wrong. That view is held by 46% of Republicans, 18% of Democrats and 28% of unaffiliateds. Overall, 47% of all adults take the opposite view and say it is not morally wrong.

In August 2001, President George W. Bush cited ethical questions in his rationale to ban federal funding for embryonic stem cell research. In a nationally televised statement, Bush said, "While we’re all hopeful about the potential of this research, no one can be certain that the science will live up to the hope it has generated."

A year ago, the President vetoed the Stem Cell Research Enhancement Act. That bill, which had been approved by the House of Representatives and the Senate, sought to allow federal funding for embryonic stem cell research on cells "derived from human embryos that have been donated from in-vitro fertilization clinics, were created for the purposes of fertility treatment, and were in excess of the clinical need of the individuals seeking such treatment."

According to the National Institutes of Health, embryonic stem cells are derived from eggs that have been fertilized in a lab via in vitro procedures and then donated for research purposes with the donors’ informed consent. Embryonic stem cells are argued to hold more promise for yielding medical breakthroughs due to their ability to produce the various cell types that make up the human body. Adult stem cells, though promising in their own regard, have limited regenerative capabilities.