I have a son with autism
Oh I see. They say parents n  otice the symp toms in the first   two or three years.t
my son's signs gradually developed- he wasn't meeting milestones at the same rate as his peers
It's not really known what causes it, I believe. A combination of genetic and environmental factors.
Right. He has had genetic testing. I know there are theories about vaccines being the root cause, but that has been disproven
I read there are almost 25 million people globally with autism.
Wow, I didn't realize the number was that high. Does that include those with asperger syndrome and PDD-NOS?
Yes, the  number has increased a lot since the 1960's, but whether actual rates have increased hasn't been resolved.