WASHINGTON — A federal judge on Tuesday refused to lift his order blocking federal funding for some stem cell research, saying that a "parade of horribles" predicted by federal officials would not happen.

Medical researchers value stem cells because they are master cells that can turn into any tissue of the body. Research eventually could lead to cures for spinal cord injuries, Parkinson's disease and other ailments.

The Justice Department argued in court papers last week that stopping the research could cause "irrevocable harm to the millions of extremely sick or injured people who stand to benefit ... 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."

U.S. District Judge Royce Lamberth rejected that argument in refusing to lift the restraining order he signed 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.

"Defendants are incorrect about much of their 'parade of horribles' that will supposedly result from this court's preliminary injunction," Lamberth said in his order issued Tuesday.

As president George W. Bush allowed taxpayer-funded research on 21 stem cell lines. President Barack Obama expanded - up to 75 so far - the number that could be used if those who donated an embryo did so voluntarily and were told of other options, such as donating that embryo to another infertile woman.

The scientists suing to stop the research "agree that this court's order does not even address the Bush administration guidelines, or whether NIH could return to those guidelines," Lamberth wrote in his latest order. "The prior guidelines, of course, allowed research only on existing stem cell lines, foreclosing additional destruction of embryos. Plaintiffs also agree that projects previously awarded and funded are not affected by this court's order."

Opponents of the research hailed Lamberth's earlier 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 lawsuit was filed by two scientists who argued that 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.

Federal officials wanted Lamberth to lift his stay temporarily while they appeal to the U.S. Court of Appeals for the District of Columbia.