The Obama administration pleaded with an appeals court Monday to overturn a judge's order halting federal funding of stem cell research, arguing the ban would irreparably harm scientific progress toward potentially lifesaving medical treatment.

A three-judge panel of the Court of Appeals for the District of Columbia is considering whether to throw out a lower court judge's ban on President Barack Obama's rules for federal funding of human embryonic stem cell research.

Chief Judge Royce Lamberth of the U.S. District Court in Washington temporarily blocked Obama's rules a month ago because he said it's likely they violate the law on federal funding of embryo destruction. He's presiding in a lawsuit challenging those rules, filed by the nonprofit group Nightlight Christian Adoptions, which helps with the adoption of human embryos that are being stored in fertilization clinics.

The appeals court stayed Lamberth's order and allowed the research to continue while it takes up the case. It gave both sides in the dispute 15 minutes each to present its arguments over the injunction, but in an indication of the high stakes in the case ended up questioning the attorneys for more than an hour.

Deputy Assistant Attorney General Beth Brinkmann told the appellate judges that Lamberth's injunction would stop funding to 24 research projects at the National Institutes of Health that have already received $64 million in taxpayer investment.

Judge Thomas Griffith questioned whether the work would really be irreparably harmed or just delayed if the government ultimately can win the ongoing case.