Based on my experience with the system, most psychologists and doctors have a pretty firm idea of what is an is not autism even if it's a bit fuzzier for the rest of us.
They do have a firm idea, but not for a good reason. Doctors want to diagnose with yes or no (and it has its legal consequences). Yet, all current evidence shows that most likely there is no sharp transition between having autism and not. For some readings, look at papers at https://www.mendeley.com/groups/519371/asperger-syndrome-and....
