Yes it is true. ANY child phsycologist will tell you that the definition of Autism as been GREATLY enlarged.
http://www.jneurosci.org/cgi/content/full/24/28/6392
Autism is a lifelong neurodevelopmental disorder that is diag-
nosed in early childhood and characterized by a core deficit in
social interaction (American Psychiatric Association, 1994).
Other components of the disorder may include language impair-
ments, stereotypical behaviors, and unusual fear or anxiety. Since
Kanner (1943) initially described the disorder over 60 years ago,
the definition of the autistic spectrum has evolved and now en-
compasses a wide range of severity of social and emotional ab-
normalities with varying levels of cognitive and linguistic func-
tioning. The disorder ranges from low functioning with mental
retardation [low-functioning autism (LFA)] to high functioning
(HFA)]. Almost simultaneously with Kanner, Asperger (1944)
described a group of children with a narrow range of interests and
impaired social interaction similar to high-functioning autism
but whose development of verbal ability was not delayed. The
distinction of Asperger syndrome (ASP) from high-functioning
autism is controversial (Klin et al., 1995; Ozonoff et al., 2000;
Howlin, 2003).
Non sequitur. (The conclusion of the first statement does not follow from the truth of the second.)
While the definition has been greatly enlarged, it does not account for all of the growth in prevalence--or severity.
Professionals who have been in the field all their adult lives and are nearing retirement have confirmed this trend firsthand.
And I am well aware of how changing definitions can inflate incidence numbers--look at my writings published 15-20 years ago and you'll find where I pointed out that the AIDS definition was expanded multiple times to keep the numbers increasing (to keep the $$$ flowing in).