The cause of autism is the source of many controversies, mainly because it is largely unknown at this time. Historically, when doctors were just starting to understand autism, many physicians believed that autism was the result of poor parenting techniques. Ironically, one of the pioneers of autism, Dr. Leo Kanner at Johns Hopkins University, first described the “refrigerator mother” theory as the cause of autism. He concluded that autistic children seem detached to other people because their mothers failed to show warmth during their upbringing. What he observed was that the parents of autistic children did not have a lot of interaction with their children, and he deduced the lack of interaction could contribute to the lack of social skills in these children. What he did not take into consideration is the fact that these parents demonstrated little interaction with their children only because these children regularly turned away their affection. After a long period of time, these parents learned to keep their distance and avoid close personal interaction with the children.

Fortunately, we now know that parents are not to blame for causing their children to be autistic. Nevertheless, there is strong evidence that autism is partly caused by genetic factors. Several facts led to this conclusion. Siblings of autistic children are much more likely to be diagnosed with autism, and autistic traits tend to run in families. Recently several genes have been identified that predispose children to have autistic tendencies.

Even though the burden of poor parenting has been lifted from parents, a genetic cause still makes many parents feel somewhat responsible for their children's plight. The guilt is not intentional, but somehow they feel blamed because the seed of autism could have come from themselves.

It is also obvious that genetics does not explain the whole story. If autism is purely inherited, you would expect all autistic children to have autistic parents, or at least autistic relatives. This is definitely not the case. So on top of having a genetic predisposition, there is something else that seems to trigger the onset of autism. It is this “something else” that is at the heart of the controversy.

Unfortunately, no one knows what the triggers are for autism. In all likelihood, there are numerous triggers that can possibly cause autism. Autism is probably the end result of a combination of genetic factors and environmental triggers. Some have hypothesized that a defective immune system plays a role in triggering autism, while others blamed environmental pollutants. Some even lay the blame on vitamin deficiency. Many parents believe that childhood vaccination plays a role in triggering autism in some children.