Reading the Permaculture Institute article below has started me thinking about some of the other factors that come into the question of what might trigger or cause autism.
One of the major observations of clinicians is that children with autism have often being exposed to antibiotics more often than those without autism. (This may be because autistic children simply get more illnesses, or may be because antibiotics predispose children to autism: it's hard to know what comes first.) However antibiotics are also sometimes one of the treatment methods in healing the gut, if there are signs of massively abnormal gut flora. What a tricky role they play!
Antibiotics, of course, reduce and sometimes completely deplete normal intestinal bacteria. This is why we all take yoghurt afterward. However if a child's normal gut flora is disrupted, might it then become more likely that the Bt toxin producing bacterial genes become established in the new gut colony? Thus a child undergoing antibiotic treatment at the time of weaning (or soon after) who also lives in a toxin-laden environment might develop more serious neurological symptoms than a child with only one of those factors, if gene transfer between Bt toxin-producing corn and intestinal bacteria is a cause.
I have no idea if this is possible or if the mechanisms exist to make it likely. But I've always wondered how antibiotic use might affect the ingestion and non-excretion of heavy metals. It seems to me that gut flora suddenly converted to mostly Bt-carrying (therefore actively and in an ongoing fashion damaging the gut wall) could be one way the intestinal lining suddenly becomes more open to toxins, and stays that way unless targeted by treatments. This may also explain to some degree why probiotics help: because swamping the gut with new bacterial genes may water down the presence of Bt producing ones.
As usual it's a question, not an answer. But something causes autism, and it seems now (despite many years since vaccination) to be causing long term digestion and attention problems in my son.