> if you doubt the diagnosis, fine - get a second opinion

We actually tried to get a second opinion. We went to another psychologist for one, she booked us in, but then her superiors cancelled it. They said if a child has been diagnosed as having ASD Level 2, they didn't want to repeat the assessment since there was a risk they might get undiagnosed or only diagnosed as Level 1, which would remove his eligibility for government disability funding (NDIS). (Which we still haven't applied for, because we aren't convinced he needs it, and don't know what to spend it on anyway.) They wanted us to go to see some paediatrician they like, who is actually a colleague of our son's existing one.

Instead we took him back to his existing paediatrician. He said he too was a bit sceptical about the diagnosis, but that psychological diagnosis isn't an entirely objective process, and it doesn't really matter whether he has ASD or not, and it would be a waste of time to repeat the assessment, so we should just do nothing about it for 6-12 months, and see how he goes, and consider repeating the assessment in another 2-3 years.