I recently stumbled across this interesting essay:

Gernsbacher, Morton Ann (2007) A conspicuous absence of scientific leadership: the illusory epidemic of autism.
http://jepson.richmond.edu/academics/projects/ESSAYGernsbacher.pdf

I think I'll add it to the list of references in my old blog article "What autism epidemic?" http://incorrectpleasures.blogspot.com/2007/06/what-autism-epidemic-allen-arthur-2007.html