Their record far outstrips that of the private banks. The three biggest private banks have provided cells for 55 transplants, according to statistics they provided. In 49 of those cases, the cells went to a sibling, most often one already sick with leukemia or another disease when the blood was stored.
But the public banks lack one thing: cachet. Many parents believe private banks offer them the most security and control.
"It is analogous to private schools and public schools," said Stephen Grant, a vice president at Cord Blood Registry.
Dr. Robert Chow, the founder of Stemcyte Inc., which runs public and private banks in Arcadia and Taiwan, said the allure of private banking was too strong for many parents to resist.
"I understand why they do it," he said. "They will feel guilty if they don't."
'THE RELIGION OF CORD BLOOD'
The emotional pull is irresistible for many parents.
"It's like a religion — the religion of cord blood," said Kenneth Worth, a Fullerton lawyer who has tried to fight cord blood companies but has struggled to find parents who feel wronged.
"People want to believe that it's true."
Reason alone is not enough to decide whether to bank.
Grant, of Cord Blood Registry, explained his strategy for handling roomfuls of skeptical doctors and scientists. He asks who would bank if the service were free. Most hands go up.
The message is clear: How could throwing something away be better than keeping it?
Sean Morrison, a stem cell biologist at the University of Michigan, had the chance to bank for free nine years ago. He sent his daughter's cells to a fellow researcher who was collecting samples.
"It's just like buying a lottery ticket," he said. "The chances of winning are extremely low, but that doesn't stop people from buying it."
When his second daughter was born two years later, storing the cells with his colleague was no longer an option. He knew what he had to do.
He signed up with Cord Blood Registry.
How could he justify banking for one and not the other?
The pressure to bank has grown as more parents choose to do it.
Annamarie Cummings of Crystal Lake, Ill., a Chicago suburb, said the issue had come up at neighborhood picnics. She said one mother regretted not banking. And lately there has been head-shaking talk about a child with leukemia whose parents apparently did not bank either.
Cummings said she and her husband, Bill, were ahead of the curve. They banked for their daughter in 1999 and for their twin sons two years later.
It is a lifetime commitment.
"We have decided to pay until all three of our children are 21 years of age," she said. "Then they can probably take it on from there."
From time to time, parents call Family Cord Blood Services hoping to come by and see the cells they banked, said Rydman, the company president.
There is nothing wrong. They just want to see.
Rydman tells them that they are free to look at the stainless steel tanks, but he explains that the samples are best left undisturbed.
The cells will keep for years and years and years, bathed in liquid nitrogen at 321 degrees below zero.