https://www.scientificamerican.com/article/the-real-reasons-autism-rates-are-up-in-the-u-s/
Is there no real increase in autism rates, then?
Awareness and changing criteria probably account for the bulk of the rise in prevalence, but biological factors might also contribute, says Durkin. For example, having older parents, particularly an older father, may boost the risk of autism. Children born prematurely also are at increased risk of autism, and more premature infants survive now than ever before.