July 12, 2005 -- The Senate is headed for a broad and heated scientific and ethical debate that could derail popular legislation designed to lift limits on embryonic stem cell research.
Lawmakers are likely to vote next week on a bill lifting stem cell funding restrictions laid down by President Bush four years ago. A majority of senators support the legislation, which passed the House by a wide margin in May.
At the same time, several lawmakers are now trying to force a debate on other contentious issues that could wind up undercutting efforts to expand funding for stem cell studies.
Senate Republican Leader Bill Frist (Tenn.) told reporters Tuesday that he has offered stem cell supporters a long-sought-after vote on a bill opening up federal funding for stem cell lines derived from embryos left over from in vitro fertilization procedures.
Researchers have pegged embryonic stem cells as an important potential source of treatments for diseases including Parkinson's, diabetes, and heart damage. Stem cells have the ability to transform into any of the body's several hundred different forms of tissues, making them a candidate for growing new cells to treat various diseases.
Despite wide support on Capitol Hill, the bill remains controversial because of objections to research requiring the destruction of human embryos to extract these stem cells. Bush has vowed to veto the legislation if it reaches his desk.
But several Republican lawmakers also want a debate on another bill that would fund research on experimental stem cell extraction methods that do not require the destruction of embryos. Supporters promote the research as a potential way to pursue studies using human embryonic stem cells without the controversy now surrounding the field.
"This is a good alternative because it may solve the ethical constraints many of us have," Sen. Tom Coburn (R-Okla.), one of the bill's sponsors, tells WebMD. Coburn, who is a physician, is among a group of lawmakers who oppose research involving the destruction of embryos.
Stem cell supporters remain concerned that funding the methods, which so far have only been tried in animals, may impede proven methods of extracting stem cell lines from human embryos.
Several scientists told lawmakers in hearings Tuesday that research should pursue new stem cell extraction methods but not if they cause a delay in expanding research on lines derived from embryos.
"I do not support delaying the pursuit of medical research on existing human embryonic stem cell lines while these more speculative methods are tested," George Q. Daley, MD, a Harvard scientist and president-elect of the International Society for Stem Cell Research, told a Senate subcommittee.
Alternative Methods Debate Risky
It also appeared Tuesday that language in the bill to set up funding for the alternative methods could legally negate an expansion of human embryonic stem cell research. A House bill forming the basis of Coburn's bill prohibits federal funding for "any research that involves the use of human embryos."
Sen. Johnny Isakson (R-Ga.), the bill's other sponsor, tells WebMD that his bill seeks to advance stem cell research. "It just draws the line at destroying the embryo," he says.
Sen. Tom Harkin (D-Iowa), a sponsor of efforts to lift the White House limits on stem cell research, cautioned that the new focus on alternative extraction methods could derail his measure next week.
"I believe there are those who want to use this approach to prevent [the expansion] from being passed in the Senate," he says.
Research on cells extracted from embryos does not involve cloning, another highly controversial method used to create stem cells. Along with Frist's offer, however, is a demand that lawmakers also vote on a highly controversial measure banning all forms of human cloning, including cloning used to create new stem cell lines.
"We should present the country with a thoughtful, broad debate on where the ethics are," says Sen. Sam Brownback (R-Kan.), the main backer of the cloning ban.
An attempt to ban all forms of human cloning could spur other efforts to preserve cloning intended to produce stem cells while outlawing cloning that produces human offspring. At that point, lawmakers could become embroiled in a wide-ranging debate that unravels efforts to expand studies on cells derived from excess IVF embryos.
"There is a real fear that it is becoming a political game now," says Sen. Orrin Hatch (R-Utah), a supporter of expanding embryonic stem cell research.