SAN DIEGO -- San Diego is the first city in the nation to participate in a new and controversial procedure -- investing their own adult stem cells for future use, according to NBC 7/39.

Dr. Ron Rothenberg is the first of five donors in the U.S. to bank his own stem cells.

Currently, adult stem cells are only used to treat certain types of cancer. But Rothenberg told medical correspondent Peggy Pico there's future uses to treat strokes, head trauma and spinal cord trauma.

Rothenberg's anti-aging clinic in Encinitas is one of a handful of satellite offices run by Neo-Stem, a New York-based company that charges donors over $6,000 to collect and store their own stem cells.

How does it work? First, patients receive shots of medicine to force their bone marrow to produce more stem cells, to make them enter their blood stream.

Then a special machine siphons the stem cells out of the blood into a bag that will be frozen and sent to a storage tank in Los Angles, NBC 7/39 reported.

But there is controversy over whether it works. Dr. Larry Goldstein, director of UCSD's stem cell research program said the process is still experimental. And he said that most of what is known about adult stem cells suggests they are restricted in their ability and that they do not grow very well.

And a recently published study from Stanford University states adult stem cells did not turn into other organ cells when transplanted.

Pico reported that in addition to the $6,000 charge to collect your stem cells, Neo-Stem charges $400 a year to store them. Some of that money goes to the doctors at the collection sites.