What are the explanations for the increase in the number of cases being diagnosed?

As you are probably aware, the rate of diagnosis of Autism and related disorders is increasing significantly. Watch the video above and do an internet search of some of the recent articles published on this topic. Write a 1 to 2 page reflection paper addressing the following issues:

Who is most commonly diagnosed (boys/girls, ages, background,etc.)?
What are the explanations for the increase in the number of cases being diagnosed?
Describe the most effective treatments, including why earlier screenings can be beneficial.
What do YOU think may be contributing to the rise in this disorder?