Liu, King, and Bearman (2010) found that independent of other factors, children living near other children diagnosed with autism are more likely to also be diagnosed with autism spectrum disorder. This demonstrates that autism spectrum disorder is:

This social phenomenon due to proximity effect. From studies children living within  certain close perimeter at least 500 meters  to  or attending the same school  with  kids diagnose with  autism have 90-100 % of been diagnose than those living far away.

Explanation:

The reason from this is the proximity effect of parents of children without autism disease to  the parents of  children diagnose  with autism.This close association enable them to   acquiring more    knowledge about the conditions, the diagnosis and methods of treatments.

Evidently studies  have shown that  children living within  certain close perimeter at least 500 meters    or attending the same school  with  kids diagnose with  autism have 90-100 % of been diagnose  with this condition than those living far away.

Therefore the method of transmission from the proximity effect is due to transmission of information from one person to another, and  not an environmental factor.The parents of children with  no autism through association with the those whose   kids  have  autism will learn about method of diagnosis, different treatment plans,the best healthcare provider to provide the best diagnostic  services  and other  necessary information.

Thus it will be easier for them to go for diagnosis of their own children too, since they have already have first hand information, this raises the number of diagnosis.

Explanation: