SAN JOSE, Costa Rica — Dr. Orlando Morales is something of a celebrity at Costa Rica’s University of Medical Science, sauntering through the halls in his white lab coat. On a recent walk, students and faculty greeted him with “Feliz cumpleanos, doctor.” He just turned 68.

With the excitement of a young doctor fresh out of medical school, Morales’ eyes light up when he observes the petri dishes that harvest “celulas madre,” or stem cells, from mice.

“It’s practically science fiction,” Morales said of what he considers the medicine's new miracle worker. Morales is one of the firmest believers around in the power of stem cell treatments.

“After a heart attack, they can begin to make new tissue. In a gland, which for example has to make insulin, the cells begin to create insulin. Nervous tissue, they regenerate it … It’s a panacea,” he said.

An increasing number of foreigners are undergoing stem cell treatment in Costa Rica for ailments from bone fractures to multiple sclerosis. Costa Rican doctors say they are providing these medical tourists with groundbreaking treatments. But stem cell scientists in the U.S. accuse Costa Rica of offering false hope by pushing techniques that have not been scientifically proven.

Dr. Fabio Solano — who directs the stem cell institute at San Jose’s CIMA Hospital, one of the country's leading private hospitals — says his team has treated as many as 400 patients with procedures that involve stem cells.

Costa Rica has eschewed the contentious debate around stem cells by prohibiting work with human embryos and instead promoting research on what's known as "adult" stem cells — derived from tissue including body fat and umbilical blood or tissue. In Costa Rica, where Catholicism is the state religion, working with human embryos is out of the question.

Embryonic stem cells are considered a goldmine that could lead to treatment for any number of ailments. Unlike adult stem cells, embryonic ones can evolve into any of more than 200 cell types.

And yet, Solano said, many "miracle" treatments have been accomlished with adult stem cells. "We have demonstrated that adult stem cells are as good as embryonic."

Success stories have grabbed media attention, with TV networks running stories like “Paralyzed valley woman holds hope in Costa Rica treatment” and “Glenburn boy returns from Costa Rica after having adult stem cell therapy.”

But the buzz has made doctors in the U.S. nervous.

“The lay press is unfortunately replete with many overstatements and misconceptions about what can be accomplished in the short term by stem cell biology,” said Dr. Jack Kessler, an expert in stem cell research at Northwestern University’s Feinberg School of Medicine in Chicago, Ill.

In March, President Barack Obama issued an executive order that lifted Bush-era restrictions on federal funding for stem cell research, but much of the treatment is still a long way off, experts say.

Meanwhile, Costa Rican legislators are putting the finishing touches on a law to promote and regulate adult stem cell research and treatment across a spectrum of diseases. This could fuel further debate over techniques that U.S. doctors say have only produced anecdotal success — but it certainly won't stem the flow of stem cell medical tourism.

According to Solano, Americans already make up close to 90 percent of the stem cell patients at CIMA Hospital.

Kessler warned that clinics around the world are exploiting patients' hopes by offering treatment that he calls a "placebo effect," and hasn't been proven to work.

“There's really little if any evidence at the present time — where we are with the current technology — that stem cell therapies are useful for disorders like spinal cord injury, stroke, Parkinson's disease, multiple sclerosis and some of the other things that are being treated with stem cells,” Kessler said.

Determined to prove the experts wrong, Jennifer Blankenship, a 49-year-old resident of Denver, Colo., made her second visit to Costa Rica in August to treat MS.

Blankenship had looked around in the U.S. for stem cell treatment but could only find offers from university labs that “wanted to charge $100,000 to $150,000 for me to be a guinea pig,” she said. Last month she underwent two weeks of treatment at CIMA Hospital for about $10,000. A December 2008 study by the journal Cell Stem Cell found that international stem cell treatment hovers around an average of $20,000.

Blankenship said that within hours of her first IV injection, “I started moving my left leg, which I hadn’t moved for years."

Following her second visit, she said, “I’m so excited,” detailing what she described as further progress toward recovery. Costa Rican doctors conducted liposuction to extract and transplant stem cells from her own fat tissue, as well as transplanted further cells derived from umbilical cords. Blankenship said she was charged up with some 200 million stem cells. “I pictured them like little Pacmen,” she joked.

After the trip, Blankenship says she took five steps, then nine. She said: “In the coming weeks, my physical therapist and I are going to my neurologist’s office to show him how I can walk.” And once she can walk on her own again, she said, “I’d love to come to Costa Rica just for fun.”