WASHINGTON – Opponents of taxpayer-funded embryonic stem cell research lost a key round Friday in a federal appeals court ruling that gives support to the Obama administration’s expansion of the promising but disputed approach to finding disease cures.

In a 2-1 decision, a panel of the U.S. Court of Appeals in Washington ruled that opponents are not likely to succeed in their lawsuit to stop federal financing of stem cell research and overturned a district judge’s order that would have blocked the funding.

The panel reversed an opinion issued last August by U.S. District Judge Royce Lamberth, who said the research likely violates the law against federal funding of embryo destruction.

The White House said the ruling was a victory for scientists and patients. “Responsible stem cell research has the potential to treat some of our most devastating diseases and conditions and offers hope to families across the country and around the world,” spokesman Nick Papas said.

Researchers hope one day to use stem cells in ways that cure spinal cord injuries, Parkinson’s disease and other ailments. Opponents of the research object because the cells were obtained from destroyed human embryos. Though current research is using cells culled long ago, opponents also fear research success would spur new embryo destruction. Proponents say the research cells come mostly from extra embryos discarded anyway by fertility clinics.

A 1996 law prohibits the use of taxpayer dollars in work that harms an embryo, so private money has been used to cull batches of the cells. Those batches can reproduce in lab dishes indefinitely, and the Obama administration issued rules permitting taxpayer dollars to be used in work on them through the National Institutes of Health.

The administration’s rules expanded the number of stem cell lines created with private money that federally funded scientists could research, up from the 21 that President George W. Bush had allowed to 91 and counting. To qualify, parents who donate the original embryo must be told of other options, such as donating to another infertile woman.

The lawsuit was filed in 2009 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.

Samuel B. Casey, a lawyer representing the plaintiffs, expressed some disappointment but no surprise at the ruling. He said they will ask the full appeals court to review it, but even if that is rejected, Lamberth “has been waiting to address other issues and the district court can fashion its decision in light of what the appeals court has told it.”

Lamberth, the chief judge of the U.S. District Court in Washington, had issued a preliminary injunction in August to block the research while the case continued. The Obama administration immediately appealed and requested the order be stopped. The appeals court quickly ruled in September that the research could continue while they took up the case.

Their answer Friday was that Lamberth’s injunction would impose a substantial hardship on stem cell research funded by NIH, particularly because it would stop multi-year projects already under way. The appellate judges also noted that Congress has re-enacted the 1996 embryo-protection law, called the Dickey-Wicker amendment, year after year with the knowledge that the government has been funding embryonic stem cell research since 2001 — evidence that Congress considers funding of such research permissible.