A new study in the journal Autism Research reports that the incidence of autism in the children of highly educated parents is higher than in the general population. Though some critics are skeptical of the study’s findings, the work does support previous research indicating a correlation between autism and the level of parental education.

The study, led by Karla Van Meter of the Sonoma County Department of Public Health, looked at data from 2.5 million families in California who had children between 1996 and 2000. Of these, the team followed 9,900 families whose children were diagnosed with autism by the age of six. The researchers found that the rate of autism was concentrated in certain areas – in fact, they found that 10 clusters existed in which the rate of diagnosis was about twice that of the general population.

But critics like Lee Grossman, president of the Autism Society of America, say that autism affects families of all socioeconomic strata, with no particular group having a greater likelihood of being stricken with the disease.

What’s more, the researchers grouped the parents according to their level of education, and found that those who were college graduates or had advanced degrees were significantly more likely to be within these higher−autism clusters.

Van Meter says that the study “confirms what we already knew, which is that highly educated parents are more likely to have children with autism.”

Why this is the case remains somewhat of a mystery, however. Van Meter adds that "[n]obody really knows for sure, but some think there may be something genetic going on, some believe better−educated parents are more successful in seeking services for their children or may have different expectations for the kids, some believe there could be some physical or chemical exposure in those households. It could be all of the above or some combination of factors. All are being studied."

But critics like Lee Grossman, president of the Autism Society of America, say that autism affects families of all socioeconomic strata, with no particular group having a greater likelihood of being stricken with the disease. The study did find, though, that the higher−autism clusters were often closer to autism treatment centers.

Grossman said in an interview that autism “seems to occur at the same rate no matter where you are and who you are. We really aren't seeing well−educated parents having a greater tendency to have children with autism." Certainly more research will be needed to determine whether the correlation found in the current study points to a real phenomenon in which more educated families are more likely to have children with autism, or whether these families are just more likely to have children who are diagnosed and treated for autism than others.

The study is in the Jan. 6 online issue of Autism Research.