WASHINGTON — Declaring that opponents of embryonic stem-cell research are "on the wrong side of history," Sen. Orrin Hatch has again unveiled legislation that would legalize the controversial research but also make it a crime to clone human beings.

Comparing stem-cell inspired treatments to the polio vaccine of generations ago, Hatch, R-Utah, said, "I believe we are on the verge of a similar step, a new generation in medical research and treatment, thanks to the incredible potential of stem cells."

The senator's "Human Cloning Ban and Stem Cell Research Protection Act" was introduced in 2003 but was never debated or voted on, although it did become a campaign issue in the 2004 presidential campaign.

Joining Hatch at Thursday's press conference were co-sponsors Sen. Dianne Feinstein, D-Calif., and Sen. Arlen Specter, R-Pa., who is undergoing treatment for a cancer "problem that may well be helped by stem-cell research."

"We do not use all of the resources available to us to fight these maladies," Specter added, referring to the potential the research has for treatment of diabetes, Alzheimer's, spinal cord injuries and Parkinson's disease.

Sens. Tom Harkin, D-Iowa, and Ted Kennedy, D-Mass., are also primary sponsors of the legislation, which would roll back President Bush's limitation of federal funding for stem-cell research to those cell lines in existence in 2001 when the ban was instituted.

Originally, there were 63 cell lines that researchers could use. That has since been reduced by about two-thirds, and supporters of the legislation said most, if not all, of the remaining lines have become contaminated and are useless to scientists.

Hatch said Bush's ban was a Solomon-like attempt to "split the baby" by allowing some limited research to continue but appeasing the Christian right that is generally opposed to embryonic stem-cell research because it involves using human eggs.

"One of the best ways to be pro-life is to take care of the living," Hatch said.

That argument is probably not going to carry the day with the right wing of the GOP, but Hatch and the others believe they do have at least 60 votes to bring the matter up for a floor debate. Hatch has talked to his party's leadership about the bill, but they made no commitment.

"They haven't said no," Hatch said.

The sponsors all agree that federal action is required in light of a hodgepodge of state legislation popping up across the nation. Five states specifically ban stem-cell research, and 20 states are considering some type of legislation. (Utah has no law and is among a minority of states not considering one.)

Four states specifically approve stem-cell research within ethical guidelines, and three of them have invested huge sums of money toward that research, led by California, which passed a $3 billion research bond.