Updated at 4:42 p.m. ET
The Obama administration on Tuesday asked a federal judge to lift a restraining order that it says could undercut federally funded embryonic stem cell research.
The Justice Department filed its request with U.S. District Judge Royce Lamberth only days after he blocked government funding of embryonic stem cell research.
Medical researchers value stem cells because they are master cells that can turn into any tissue of the body, and they expect the research to eventually lead to cures for spinal cord injuries, Parkinson's disease and other ailments.
Stopping the research could cause "irrevocable harm to the millions of extremely sick or injured people who stand to benefit" from continuing human embryonic stem cell research, the department said in court papers, "as well as to the defendants, the scientific community and the taxpayers who have already spent hundreds of millions of dollars on such research through public funding of projects which will now be forced to shut down and, in many cases, scrapped altogether."
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It was not immediately known when Lamberth would make a decision on the government's petition. Federal officials also indicated that they plan to appeal Lamberth's ruling to the U.S. Court of Appeals for the District of Columbia.
Lamberth signed the restraining order after ruling that the argument in a pending lawsuit - that the research violates the intent of a 1996 law prohibiting use of taxpayer dollars in work that destroys a human embryo - was likely to succeed.
That law, called the Dickey-Wicker amendment, was written several years before scientists began growing batches, or lines, of stem cells culled from embryos, and President Obama and the two previous administrations had made a distinction between them and stem cell research.
The Justice Department said Congress has made that same distinction. In fact, Justice officials said, lawmakers have expressly endorsed the view that HESC research is not barred by the Dickey-Wicker Amendment through its funding for the National Institutes of Health.
"In light of the endorsement by Congress of that rational, long-standing interpretation - an endorsement that was magnified by Congress's approval of the interpretation in the recent passage of the 2010 appropriations for NIH - defendants respectfully assert that their interpretation is consistent with the language of the statute and congressional intent," Justice officials said.
Opponents of the research hailed Lamberth's ruling, saying such federally supported studies are prohibited by law because human embryos are destroyed in order to extract the stem cells.
Culling embryonic stem cells does kill a days-old embryo, so doing that must be funded with private money. But once the cells are culled, they can reproduce in lab dishes indefinitely. Hence, government policies said using taxpayer dollars to work with the already created batches of cells are allowed.
The Justice Department pointed out in court papers that not only will Lamberth's order affect research authorized by Mr. Obama, but also that authorized by his predecessor, President George W. Bush.
Bush allowed taxpayer-funded research on 21 stem cell lines. Mr. Obama expanded - up to 75 so far - the number that could be used if the woman or couple who donated an embryo did so voluntarily and were told of other options, such as donating that embryo to another infertile woman.
Lamberth's order covers "research that has been ongoing for years, including under the policies of the prior administration," officials said.
The lawsuit was filed by two scientists who argued that Mr. Obama's expansion jeopardized their ability to win government funding for research using adult stem cells - ones that have already matured to create specific types of tissues - because it will mean extra competition.
"It is highly doubtful that plaintiffs' economic or professional interests will be affected in any way if the injunction is stayed," Justice Department spokeswoman Tracy Schmaler said in a statement Tuesday. "Applications for research they conduct are not in direct competition with human embryonic stem cells research."