WASHINGTON - John and Mary Arnaudo of Ripon were near desperation last year after their 8-year-old daughter, Francesca, was diagnosed with leukemia.

To kill the cancer, Francesca's body would have to be irradiated and injected with chemicals so toxic that they would destroy her ability to replenish her blood. To restore her health, she would need a transplant of the cells that can regenerate blood - stem cells.

Finding no blood match within their family or the National Bone Marrow Donor Registry, help finally came from an anonymous woman who will never know the life she helped save.

 Blood extracted from the placenta and umbilical cord after the woman gave birth is now helping Francesca rebuild her blood supply and fight off the cancer.

"We are very fortunate, thankful and grateful," said Mary Arnaudo.

Cord blood is the flip side of the huge battle in Congress over stem cells.

Now, some are worried that the controversial fight over embryonic stem cell research is stalling congressional action over legislation that could transform the medical waste of childbirth into the primary source of cells for treating leukemia, sickle cell anemia and dozens of other blood-related diseases.

At a Capitol Hill press conference earlier this month, a half-dozen children whose lives had been saved by cord-blood transplants joined basketball legend Julius "Dr. J" Erving and a half-dozen House members in appealing to the Senate to quickly enact House-passed legislation that would create an expanded national cord-blood program.

"Delay is denial" for those who need it now, said Rep. Chris Smith, R-N.J., chief sponsor of the legislation. "Waiting another six months or a year is a death sentence."

Many of the advocates of the cord-blood bill are opposed to research on embryonic cells that, though far more promising in its potential for curing disease, involves use of human eggs that could become human beings.

One of the most passionate voices at the press conference, for example, was Rep. Dan Lungren, R-Gold River, a conservative Catholic and a fierce opponent of expanded embryonic stem cell research.

"While we argue about other stem cells, there is no excuse to sit here and refuse to move this legislation that will save lives now," Lungren said. "Shame on us if this goes on much longer."

Indeed, it was the building pressure for federal embryonic stem cell research that moved the House to take up the cord-blood bill. The measures were brought up together in May by the House Republican leadership, thus giving members opposed to embryonic research a stem cell bill they could support.

The cord-blood bill passed 431-1. Expanded embryonic research passed 238-194 - a margin too small to overcome a promised veto by President Bush. Both bills now languish in the Senate, as embryonic stem cell supporters resist passing one bill without the other.

Philip Coehlo, head of Rancho Cordova-based ThermoGenesis Corp., which makes equipment to freeze and store stem cells, said the political dynamics remain tricky.

"This bill is caught up in politics," he said. "There are people who don't want Bush to sign anything with the words 'stem cell' in it. They are worried about him then saying that he's done everything he can on stem cells."

Dr. Douglas Taylor, director of pediatric bone marrow transplantation at the University of California, Davis, Medical Center, is one of Francesca's doctors, and he oversaw her cord-blood transplant.

Taylor often feels caught in the bigger fight over embryonic stem cell research, which he also supports. He chooses to use the term "bone marrow transplants" even though what's being transplanted is blood stem cells, for which bone marrow is a decreasingly important source.

"I try not to use the words 'stem cells' because of the political implications," he said in a telephone interview.

As in the case with Francesca, Taylor said, the difficulty in saving the lives of someone needing a blood stem cell transplant is in finding a donor.

The national registry of bone marrow donors is limited, and the process of extracting the cells from those willing to do it involves needles inserted into the hip under anesthesia in a hospital operating room. The cells also can be filtered from a donor's blood, but that process involves being hooked up to machines for six or more hours, he said.

But cord stem cells are as close as the nearest hospital delivery room. Cells filtered from that umbilical blood can be frozen and stored, ready for computer sorting through a national database and deliverable to a needy patient on the next airplane.

That's what happened with Francesca, Taylor said.

"When there was no suitable donor within her family, we had to look outside," he said. "The donor we found turned out not to be a person, but already stored cord blood from the New York Blood Center."

Francesca had an easier time than many in finding a match, Taylor said. She is Caucasian, and for Caucasians there is a 50 percent chance now of finding a suitable cord-blood match from the frozen stock.

But it's not so easy for other ethnic groups. And because blood has characteristics tied in part to the donor's ethnicity, there is great need to increase the supply of cord blood from other ethnic groups and mixed races.

That's what the federal legislation would do. It would fold the National Bone Marrow Donor Registry into a national cell transplantation program with $186 million over five years to build an ethnically diverse cord-blood bank of 150,000 units.

The bill's goal is to have enough cord blood in storage within five years that any patient would have a 90 percent chance of finding a suitable match. In time, supporters said, cord blood likely would replace entirely the costly and painful extraction of blood marrow.

According to Taylor, one of the biggest obstacles now is that the volume of stem cells from a discarded umbilical cord is too small for adult-size transplants. Research is under way to perfect combining matching blood units.

"When the issue of size is overcome, the only reason to use anything else would be availability," he said.

There is virtually no disagreement on the virtue of the bill's goal ending the availability problem. The only opponent of the House-passed bill was Rep. Ron Paul, R-Texas, who says he thinks any federal funding of stem cell research is unconstitutional.

The Senate bill has 33 co-sponsors, including Senate Majority Leader Bill Frist, R-Tenn., who has the power to schedule bills for a vote.