Here is a link to the DSM IV (current) criteria for diagnosing autism. As you can see, the criteria can come from a number of different categories which is why one poster notes that none of her students with autism are the same. Of course, people with autism are just as unique as any other person so I am always confused as to why people expect them to be the same. In any case, the DSM V will change the criteria for receiving an autism diagnosis.
Bruno Bettleheim wrote the book The Empty Fortress: Infantile Autism and the Birth of the Self in the 1960s. Even then, the "refrigerator mother" theory was on its way out.
Statistically, boys are approximately 4-5 times more likely to have autism than girls.
As someone who has a child on the autism spectrum and had the flu while pregnant, I am sweating this statistic 0%...and my odds of having another child on the spectrum are quite a bit higher than 2%. :)