This is in my opinion a good article covering the increase in autism diagnosis. I think the main conclusion that this reflects changes in diagnostic practise, rather than changes in ASD rates per se, is likely true. However I thought the article was a little brief/dismissive of possible environmental contributants including pollution, dietary changes etc. Whilst these are largely unproven, this does not mean that there is no potential link and more research is really needed to understand whether there is a "true" increase in rates as well as apparent increases due to changes in diagnostic practices and services etc