I just read about this. 

Something researchers can measure in the blood is the presence of persistent organic pollutants. "Many of them have been banned, but they are so persistent in the environment that we continue to be exposed and they're persistent in our body because they're stored in the fat tissue and they can stay in the body for a long time," Hertz-Picciotto said.

Pesticides used in agriculture and household products such as ant sprays have drawn the attention of researchers. One study in the Central Valley found that children with autism-like symptoms had higher levels of pesticide byproducts in their urine.

What do you think?