When people mention environmental toxins may cause autism, what exactly are these factors?

Nobody really knows: Some people have a theory that toxins in the environment may be one of the causes of autism. The word toxins refers to substances that are increased in our world due to our modern, industrialized society. That means all the things that we use, or that are used to produce the goods we have, can be the toxins in our environment. There are too many chemicals or substances to count.

Some epigenetic : Factors that change function, but not structure or sequence of fetal genes (e.g., alcohol, tobacco, drugs, some medications, heavy metals, some infections, & ?ed maternal folate (folic acid) levels) ? risk of neurodevelopmental disorders like autism in offspring. Fetal brain development starts 3 wks. Post-conception, so folate (folic acid) supplements & avoidance of toxins must be in place before conception to ?risk.