I don't know a lot about autism but I do know that there has been a huge increase in incidence in recent years. If most of it is genetic then presumably the gene/s in question have previously laid dormant. There must be something in our modern environment that is now acting as a trigger for these genes.

As someone that has what is considered a very high success rate in handling autism spectrum disorders and getting the body to reverse the condition I will tell you with absolute certainty without question that metals have EVERYTHING to do with this condition because It is ALWAYS in the brain tissue when I test these children and they ALWAYS respond and get better when it comes out.  End of story.  The metals do not always come from vaccines and the majority is actually passed through the placenta.  Moms ALWAYS have high levels of Metals in their body (but not the brain) so they do not know it.  By the way, The ANSWER TO AUTISM is NOT the often harsh chelation therapies like DMSA, DMPA, EDTA as they do not work very well to begin with and can in fact do harm as I see these children and fix them after they went that route.  I learned and used to use this approach as a DAN practitioner and it does not work well.  There is a superior and safer way that is 100% effective as long as all sugar is removed from the diet.  When the metals come out and the levels are low enough inside the body, a transformational shift takes place and they act and behave like normal children.  Enough said.  This is the truth and the sooner it is accepted the better off we will all be