A new study has come up with the rather bizarre theory that watching too much television at an early age may trigger autism.
The study by Cornell business professors used the methods and tools normally used in economic studies to explore the theory that the increase in autism cases came at the same time as increased opportunities for very young children to watch TV.
The rapid rise in the number of children diagnosed with autism over the last few decades, has led to a great deal of speculation as to the cause.
Childhood vaccines, toxins and genes are just some of the suspected culprits which have been proffered but nothing specifically points to a definite reason for the condition developing in some children.
Many experts believe the increase is due to broader diagnostic criteria for autism and the increased services now offered for autistic children.
Others persist in the belief that something in the environment is triggering an autism epidemic.
Professor Michael Waldman, Ph.D., says the increase in autism cases came at the same time as increased opportunities for very young children to watch TV and questions whether the explosion in children's TV programming, DVDs, VCRs, and video/computer games is behind the explosion in autism diagnoses?
He has he says evidence which suggests that is the case.
Autism is as a rule diagnosed when a child is about 3 years old, therefore any effect of TV watching would have to happen before that age.
Waldman says there are few studies which have examined the TV habits of toddlers in the U.S.
Statistics from the U.S. Bureau of Labor Statistics, on when families watch TV and how much TV they watch, show that toddlers watch more television when it's raining outside than when it isn't raining.
For the study Waldman and colleagues looked at county-by-county autism rates in California, Oregon, and Washington, three states which have huge regional variations in annual rainfall.
Waldman and his team found that autism rates were higher in the rainiest counties.
The researchers say if it rains more, autism goes up and if it rains less, autism goes down.