According to the scientific information that I have read and heard, the brain is the last part of the body to complete its development. Babies are thought to be born with extra neural connections for redundancy and for hyper-awareness that enables the quick learning of many complex skills through observation. Normally a pruning process occurs as we age to prevent an excess and crossing of signals generating overload. Epilepsy and autism seem to be the result of the this process going wrong to varying degrees. Too many remain, between hemispheres or throughout the brain. The pattern and amount of the extra connections seem to create the spectrum as well as the uniqueness of each individual's place on the spectrum.
Could it be possible that a lack of microbial contact caused by a cesarean section, sterile formula in sterile bottles, and/or an antibacterial environment could increase the risk of developing autism? If so, then carpeting-bombing with antibiotics wouldn't help and a normally helpful vaccine or a relatively harmless additive could accidentally kill enough existing microbes to trigger the autism they may be keeping at bay. No conspiracies needed, if any of this is true, just misguided, uniformed good intentions.