Senators who want the public to pay for human embryonic stem cell (search) studies said Tuesday that Congress must first pass legislation to lift President Bush's (search) restrictions on such research before paying for unproven alternative methods favored by conservatives.

"I'm all for these alternative sources ... let's go ahead and pursue them. But we already know how to derive stem cells," said Sen. Tom Harkin (search), D-Iowa. Harkin, with Sen. Arlen Specter, R-Pa., is sponsoring a House-passed bill to lift Bush's restrictions on stem cell research.

Testifying Tuesday were four scientists whose alternative research is being considered by Bush, Senate Majority Leader Bill Frist and other conservatives who want to vote for embryonic stem cell legislation that does not destroy budding human life.

Frist, R-Tenn., wants to bring up four to five such bills as alternatives to Specter-Harkin to give senators a way to vote for embryonic stem cell research without crossing constituents who harbor moral concerns.

While interesting, the methods aren't worth funding without passing the Specter-Harkin bill, the sponsors said. One of the scientists agreed.

Robert Lanza, vice president of medical and scientific research for Advanced Cell Technology, which is developing one type of alternative research, called any choice between the Specter-Harkin bill and a conservative alternative that might fund his own studies "a no-brainer."

"We need to pass (H.R.) 810," he said, referring to the House-passed version. "I do not think we should keep the scientific community or the patient community waiting."

But William B. Hurlbut of Stanford University told the panel that Congress should first support bills on which there is ethical consensus and provide "a coherent moral platform to guide our science."

Harkin didn't budge.

What "we're discussing today hasn't been published in a single scientific journal," Harkin said. "It hasn't even cleared the peer review process. It hasn't been tried in mice. We're a long way from proving it works with human embryos.".

Harkin said that "if we're going to fund these alternative approaches, that's fine — if we don't stop the process that we have right now of deriving embryonic stem cells that have so much promise for cures."

Specter, a cancer patient angry at the delay caused by Bush's 2001 ban on federal funding for new embryonic stem cell lines, made clear that his bill is the first priority.

"If we can pass the House bill, Specter-Harkin, that is the most important bill to be enacted," Specter said as he gaveled open the Labor, Health and Human Services subcommittee hearing.

Testifying were James Battey, chairman of the National Institutes of Health Stem Cell Task Force, and Lanza, who has done research into deriving stem cells from a single animal cell without destroying the embryo. He urged panel members to vote for the Specter-Harkin bill in addition to any legislation that would fund his own research.

"Further investigations should be funded and encouraged" to see if "stem cell lines can be derived in humans using these approaches," Lanza said in prepared remarks.

Bald and gravelly-voiced from cancer treatments, Specter said the debate itself makes him angry.

"Yeah, well I am, as a matter of fact," Specter said. "Try a few chemotherapy treatments and see how you feel" watching others debate medical research funding.

"The potential for stem cells has been held in abeyance much too long," Specter said.

Specter said he will lift his self-imposed ban on discussing personal matters on the Senate floor and frame the debate in intimate terms — including a "long list of my medicines and my ailments."

"And I'd like to see a million-person march on the (National) Mall," Specter added. "That's an idea that has run through my chemotherapy-occupied cerebrum."