Researchers from Cornell University said they have discovered a link between TV watching and autism.

The authors looked at county-by-county information on when cable TV entered an area, as well as precipitation rates.

The analysis showed that children from rainy counties watch more television and that areas with high precipitation also had higher autism rates.

"The analysis shows that early childhood television viewing could be an environmental trigger for the onset of autism and strongly points to the need for more research by experts in the field of autism," said Michael Waldman, a professor of economics at Cornell's Johnson Graduate School of Management.

A news release from Cornell reported that the autism rate was 1 in 2,500 children 30 years ago, but has increased to as high as 1 in 166 as TV viewing has increased.

The authors looked at indirect views such as weather and cable penetration rates because there was no data to track autism against how much time children spend watching TV.

"Our analysis is not definitive, but it certainly raises questions that seem to have gone unasked in autism research to date," said Sean Nicholson, an associate professor of policy analysis and management at Cornell.