Endless, Pure New Blood From Stem Cells?

It's a doctor's dream -- an unlimited supply of disease-free blood.

And it may not be the stuff of fiction for long, reports CBS News correspondent Elizabeth Palmer.

Someone in the United States needs blood every two seconds. In surgery, on cancer words, on the nation's battlefields -- blood transfusions save lives.

But in the U.S., demand often exceeds supply. And elsewhere, especially in the developing world, there's a real chance the blood cud be contaminated with diseases such as AIDS or Hepatitis C.

Enter Dr. Marc Turner, a cell biologist from Scotland who received a multi-million dollar research grant to try to make blood in his lab from human stem cells.

"These cells are being generated from human embryonic stem cells, which themselves are generated from three-to-five-day-old human embryos," Turner says.

Palmer explains that stem cells can be coaxed, theoretically, to grow into any human body part.

Turner's team will try to make them grow into O- negative blood -- the universal donor type, useful in the vast majority of transfusions.

If they're successful, the payoff is huge: a limitless supply of blood.

Dr. Gail Roboz, a New York hematologist leukemia researcher told CBS News, "We want the fantasy; we would like a purely clean and limitless blood supply and I can tell you that, in giving a patient a consent form for a transfusion, (if) we were able to say there isn't a chance of communicating hepatitis or HIV or any of the disease that are so scary for patients, it would be a tremendous relief. And we'd never have to say to a patient, 'We don't have blood for you today' -- that would be tremendous, as well.

"The fantasy here -- what would be phenomenal -- would be if we could create infection-free blood that's laboratory generated, so it's not dependent on donors and their availability and their willingness to come in and donate. But rather, something that the doctors could actually mine in the laboratory and have available for patients in an as-needed basis. For example, if there would be a disaster of some sort, to actually rev up the process and make more.

"As a leukemia doctor, and a doctor who treats bone marrow failure, almost all of my patients are heavily transfused and dependent on the blood supply. And we worry -- there are definitely times when people will come in and we won't have the right type of blood available, or we might have to wait an extra day to find one."

Martin King's post-cancer treatment means he needs blood every three weeks.

In spite of careful matching, he knows there remains a minute chance one of his transfusions could be contaminated, or there won't be enough.

"If there's a way to make sure that the blood supply never goes down, that would be extremely helpful," King understates.

Scientists, who hope to start testing on human volunteers within three years, think stem cell blood for widespread use is still a decade away though, for millions around the world, it can't come soon enough.