My friend Martha's friend who is autistic also had no enamel on his
deciduous molars -- pointing to a 4th month in utero insult of some sort
that resulted in the defective enamel, as well as disturbances in brain
development.  She probably had a viral infection of some kind that she
doesn't even remember.  Many cases of autism, and my nephew's seizure
disorder, can be traced to insults in utero.

There has been one (1) study of autism and infant feeding method and found a
reduced risk (!) of autism in breastfed children -- the authors attribute it
to the much lower incidence of pneumonia in the breastfed children, and
point out that other studies have implicated pneumonia in the first few
months of life as being a cause of some cases of autism.

P.S.  Cathy Liles points out, quite rightly, that she is one of my best
friends and isn't named Martha!  Sorry Cathy, didn't mean to leave you out!

Katherine A. Dettwyler, Ph.D.
Texas A&M University