The US government asked a federal appeals court to lift a court order blocking federal funding for research involving human embryonic stem cells.
US District Judge Royce Lamberth's order causes "direct and immediate" harm to federally-funded embryonic stem cell research and "potentially blocks life-saving medical advances," Obama administration lawyers told a federal appeals court in Washington.
On Tuesday, Lamberth rejected the White House's request to drop his order to temporarily block federal funding for embryonic stem cell research pending an appeal of the decision.
He said the federal funding, which Obama had authorized, violated the Dickey-Wicker amendment, a federal law barring federal tax funds from being used to fund any research that would cause human embryos to be destroyed.
That decision prompted the White House to say it would seek ways to keep the "life-saving" research going.
Obama's March 2009 decision to reverse the ban on federal funds research on embryonic stem cells was lauded by many researchers who believe the field has huge potential for treating serious diseases, including Alzheimer's, Parkinson's and diabetes.
It came after his predecessor George W. Bush had banned federal funding for research on new stem cells for moral and religious reasons.
The research is fiercely opposed by religious conservatives, who believe that life begins at conception, because it involves the disposal of embryos.