I watched " Girls with Autism" last night on ITV , and what became clear was how middle class the girls were at the high functioning specialist school.
This tallies with my own experience of attending adult support groups for autism. This is dreadful because it seems that either high functioning autism is linked to high achieving or "prosperous" , or more likely not picked up with children/adults from more disadvantaged circumstances. This means that those not getting any help, are liable to end up in jail or on the street The diagnosing of HFA tends to be linked supportive families, therefore how many people needing help get none.
I was diagnosed two years ago at the age 38 mostly to access support for Open University studies. My mum always knew i was different from my two sisters, but did not want me "labelled" therefore did not seek a diagnosis for me.