Autism affects as many as 1 in 60 boys in the United States today. Overall, 1 in 110 kids are diagnosed with autism spectrum disorders. This rate is a huge increase from my own childhood 20 years ago, when autism was something I heard about in movies but never saw in a classroom.

The surge in diagnosed autism cases is huge. Autism was first diagnosed as a unique condition in the 1940s, and was a relatively rare condition for 50 years after that. In the 1990s, diagnoses began climbing. In the decade spanning 1993 to 2003, schoolchildren with autism spectrum diagnoses increased 800%.

What happened? Theories on what's sparked the increase range from expanded diagnostic criteria that put more kids under the autism umbrella, to vaccines, to something in the water.

As theories are proposed, scientists and doctors diligently study them. So far all they've come up with is dead ends and false leads.

The Daily Green reports another potential causal link this week. Researchers in California have identified autism "hot spots" throughout the state and researched various conditions in those areas. They expected to find evidence of environmental factors causing autism in places that are, for example, heavily exposed to industrial toxins.

Instead, the only correlation they came up with was that these "hot zones" feature parents with higher-than-average levels of education and closer proximity to autism treatment centers.

Is this just an issue of over-diagnosis and over-concerned parents, then?

Probably not. Autism is such a serious illness that people often move to be near one of these treatment centers, says autism expert Dr. Cathy Pratt. In addition, educated parents are more likely to be aware of the disability and discuss its early symptoms with their child's doctor.

Disseminating information about autism in disadvantaged communities is often a challenge, Pratt said. Therefore, rather than the offspring of educated parents suffering from an over-diagnosis, some autistic kids are more likely being misdiagnosed and untreated in less affluent, less well-educated communities.

Researchers are still looking at possible links between the spike in autism diagnoses and environmental toxins, diet, genetic factors and other factors. While there are no definitive causes yet, current research points to some combination of those risk factors.

Experts in the field also acknowledge that the expansion of diagnostic criteria for autism spectrum disorders helped to both raise awareness of the problem and identify as autistic kids who previously would have been treated for other disorders or simply pegged as weird. The first widely distributed tool for diagnosing autism was published in 1991; the DSM altered the autism diagnoses to become a spectrum disorder in 1992.

There is fierce debate about whether or not these changes contributed to the sudden rise in autism diagnoses.

One thing most scientists have ruled out is vaccines. Just last month, Andrew Wakefield, the British doctor who most famously made the case for a connection between childhood vaccination and the increase in autism was slammed by the British Medical Council for his unethical behavior. Shortly after that, the Lancet retracted Wakefield's famous and controversial research.

Vaccines are not causing the autism epidemic, no matter what Jenny McCarthy says.

What do you think? Has a child in your life been affected by autism? Would you move to be near a treatment center? Might the California hot spots simply be an artifact of highly educated parents who want the best for their kids, or is there more going on there?