Recently, it was announced that the FDA had approved a clinical trial of the use of stem cells to treat autism.  At The Thinking Person's Guide to Autism, Emily Willingham is skeptical:

In the midst of all of this celebration and starry-eyed excitement about stem cells, however, the consumer would do well to proceed with caution. The trial suffers from two paradoxical issues. First, there doesn’t seem to be a specific autism-related rationale for treating children with stem cell injections...

There is a real essence of “stem cells are hot and autism is hot so lets throw some stem cells at autism” here. Science and clinical trials involving a pediatric population in particular shouldn’t rely on the “throw it at the wall and see if it sticks” mode of testing. Regardless of how safe the protocol is, administering even intravenous infusions to an autistic child can be traumatic for everyone involved. A trial like this seems hasty and the ballyhoo surrounding it overstated and overpromising.

Researchers in San Diego have created a the first human model for studying the development of autism, using stem cells from an adult from Rett syndrome.  Researcher Alysson R. Muotri exlains:

Often, it's hard to test autism treatments in animals because it's difficult to see the physical manifestations of the disorder — researchers can't observe the impaired social interactions and communication that are the hallmarks of the disease in humans, Muotri said. Until now, the only other solution was drug testing directly in humans.

"Now, we're proposing that, before going to humans, we test in cells," he said.

Click here to read more.