Yesterday, the Senate voted in support of H.R. 810, the Stem Cell Research Enhancement Act, which would lift President Bush’s restrictions on one of the most promising fields of biomedical investigation of our day. Supporters included many of the Senate’s staunchest pro-life members, including Majority Leader Bill Frist (R-Tenn.) and Sens. Orrin Hatch (R-Utah) and Trent Lott (R-Miss.).

The president has made clear his threat to veto H.R. 810 if it reaches his desk. It would be his first ever while in office. But the science of embryonic-stem-cell research is moving quickly, and much has changed since the president announced his restrictions nearly five years ago.

In light of those changes, I urge the president to sign H.R. 810 and to allow this lifesaving research to go forward.

By studying how stem cells are transformed into the whole gamut of specialized cells (muscle cells, heart cells, etc.), scientists expect to gain valuable insights into the processes that lead to Parkinson’s disease, juvenile diabetes and other medical conditions. In addition, they expect that embryonic stem cells could offer an endlessly renewable source of replacement cells and tissues for treating everything from spinal-cord injuries to osteoarthritis. But, today, our best scientists are being left on the sidelines as their colleagues overseas move forward.

When President Bush announced his policy on embryonic-stem-cell research, he said that 78 stem-cell lines were eligible for federally funded research — stem-cell lines that were derived before the arbitrary date and time of Aug. 9, 2001, at 9 p.m. But today only 21 of those 78 lines are available for research — not nearly enough to reflect the genetic diversity that scientists need.

After several years, those lines are becoming less and less stable; in a sense, one scientist told me, the lines themselves are getting sick. And most important, all 21 lines are contaminated with mouse cells, making it unlikely that they will ever be used in humans.

So the president’s policy is not a way forward; it has become a dead end. It offers only false hope to the millions of people across America and the world who are suffering from diseases that could be cured or treated through research on embryonic stem cells. We need a policy that offers true, meaningful hope to these patients and their loved ones.

H.R. 810 was sponsored in the House by Reps. Mike Castle (R-Del.) and Diana DeGette (D-Colo.), and it passed there with a strong bipartisan majority. I joined with Sen. Arlen Specter (R-Pa.) and others to champion H.R. 810 in the Senate.

Our bill would expand the number of stem-cell lines that federally funded scientists can study by lifting the arbitrary eligibility date of Aug. 9, 2001. All stem-cell lines would be eligible for federal research, as long as they meet strict ethical requirements.

Since August 2001, scientists have made great advances in deriving stem-cell lines. Many of the new lines were grown without mouse feeder cells. Shouldn’t our top scientists be studying those lines, instead of being limited to 21 lines that will never be used in humans? We don’t require our astronomers to explore the heavens with 19th century telescopes, and we don’t require our geologists to study the earth with a tape measure.

It’s important to emphasize that none of the additional lines would require the creation of new embryos. Instead, these lines could be derived from any of the more than 400,000 embryos that are left over from fertility treatments. H.R. 810 would not allow federal funding to be used to create or destroy human embryos. The bill deals exclusively with embryos that are otherwise going to be thrown away.

The choice before us is to discard unwanted embryos as just so much medical waste or to use them in research to cure disease and save lives. It is the second choice, I believe, that is truly moral and truly respectful of human life.

My nephew Kelly is one of those people whose hopes depend on stem-cell research. He has been a quadriplegic for 27 years, since suffering a spinal-cord injury in a tragic accident on an aircraft carrier. Kelly’s great hope is that research on embryonic stem cells will lead to a breakthrough that might allow him to walk again.

Kelly — and millions of other Americans suffering from disease and paralysis — have waited long enough. Our best scientists are eager to move forward aggressively with this lifesaving research. With the stroke of his pen, signing H.R. 810 into law, President Bush can say yes to science and yes to life — and he can ensure an enduring legacy of biomedical achievement.

Harkin is a member of the Appropriations and Health, Education, Labor and Pensions committees.