What Causes Autism?

If we knew the answers, this website would not need to exist!
 
Autism is approximately four times more common in boys than in girls. No two people on the autism spectrum are alike. This is why it is proving so difficult to uncover the underlying causes. There are many theories about the origins of autism, none of which have been proven, but in recent years there has been an increasing acceptance that it may be caused by a genetic susceptibility to an environmental insult. Indeed the genes themselves may have been affected by something in the environment, even before conception. 
 
Fortunately recent advances in technology, such as fMRI, Tandem Mass Spectrometry, and DNA microarrays, have opened up the doors to enable scientists to tackle the issue.