A federal judge on Monday temporarily blocked government rules expanding stem cell research, a blow to the Obama administration that could stall potentially lifesaving research.

The nonprofit group Nightlight Christian Adoptions contends that the government's new
guidelines will decrease the number of human embryos available for adoption and
implantation. Nightlight helps individuals adopt human embryos that are being stored in
fertilisation clinics. The group provides domestic, international and embryo adoption
services to families in all 50 states.

A federal appeals court had ruled that two fellow plaintiffs - doctors who do research
with adult stem cells, James Sherley of the Boston Biomedical Research Institute and
Theresa Deisher of AVM Biotechnology - were entitled to sue over the new guidelines,
prompting US. District Judge Royce Lamberth on Monday to reverse a decision he made
in October when he dismissed the lawsuit.

Sherley and Deisher allege that the guidelines will result in increased competition for limited federal funding and will injure their ability to compete successfully for National Institutes of Health stem cell research money.

Federal law explicitly forbids use of taxpayer dollars to destroy a human embryo - and culling stem cells from an embryo does destroy the embryo. However, once created,
these batches of stem cells, or lines, can reproduce indefinitely in lab dishes.

The Obama administration expanded the number of stem cell lines created with private
money that federally funded scientists could research, up from the 21 that President, Mr
George W. Bush, had allowed to 75 so far. To qualify, the NIH insisted on evidence that
the woman or couple who donated the original embryo did so voluntarily and were told of
other options, such as donating to another infertile woman.

Lamberth concluded that those filing the lawsuit have demonstrated a strong likelihood
of success in arguing that the new government guidelines violate the intent of the law
about federal funding of embryo destruction.

"As demonstrated by the plain language of the statute, the unambiguous intent of
Congress is to prohibit the expenditure of federal funds on 'research in which a human
embryo or embryos are destroyed,'" the judge wrote.

Having concluded that the law is unambiguous, "the question before the court is whether ESC research is research in which a human embryo is destroyed. The court concludes that it is," Lamberth added.

The judge's ruling drew praise from the Alliance Defence Fund, a group of Christian
attorneys and co-counsel in the suit.

"The American people should not be forced to pay for experiments - prohibited by
federal law - that destroy human life. The court is simply enforcing an existing law
passed by Congress that prevents Americans from paying another penny for needless
research on human embryos," Steven H. Aden, ADF's senior legal counsel, said.

Stem cell research has the potential to produce breakthroughs in treating life-threatening conditions - from spinal cord injury to diabetes to Parkinson's - that have resisted traditional treatment. Scientists say they need to do research with embryonic stem cells as well as so-called adult ones because the former are more flexible, and the NIH is funding both types.

"This injunction blocks important research on how to unlock the enormous potential of
human embryonic stem cells," said Sean Tipton of the American Society for
Reproductive Medicine, a group that treats infertility and does research with a variety of stem cell types. "It will be incredibly disruptive and once again drive the best scientific minds into work less likely to yield treatments for conditions from diabetes to spinal cord injury."

Tony Perkins, president of the Family Research Council, a conservative public policy foundation, called the decision "a stinging rebuke to the Obama administration and its attempt to circumvent sound science and federal law."

The NIH declined to comment, referring calls to the Justice Department, where
department spokeswoman Tracy Schmaler said the ruling was under review.

In his ruling, Lamberth said the injury of increased competition that Sherley and Deisher would face because of the guidelines "is not speculative. It is actual and imminent.
Indeed, the guidelines threaten the very livelihood of plaintiffs Sherley and Deisher."

Nightlight helps individuals adopt human embryos that are being stored in fertilisation clinics. It began the program in 1997, using some of more than 400,000 frozen embryos.

The group's executive director, Ron Stoddart, said the organisation was "pleased" with
Lambert's ruling, although he said "we're not sure what the Justice Department will do."