Why do the Amish not get autism

Dan Olmsted http://en.wikipedia.org/wiki/Dan_Olmsted

Dan Olmsted is an investigative reporter and senior editor for United
Press International (UPI), and wrote The Age of Autism report series
about autism. His columns on health and medicine appeared regularly in
the Washington Times and were syndicated nationally from UPI's
Washington D.C. bureau.

From January 2005 through July 2007, Olmsted wrote about his
investigative findings concerning the possibility that autism's
incidence rate has risen throughout the United States and elsewhere in
a series of columns titled The Age of Autism. Though most mainstream
experts think autism is a genetic disorder and that reported increases
are due to changes in diagnostic practices, Olmsted thinks the
increases are due to environmental factors and that the genetics is
mostly secondary.[1]

""By April, 2005, Olmsted had begun searching for children who had not
been exposed to mercury in vaccines, the kind of population that
scientists typically use as a 'control' in experiments. Because of the
unlikelihood of finding a large enough group of unvaccinated children
to compare with those who have been vaccinated, Olmsted learned,
government medical officials have not yet conducted an epidemiological
study with such a control group -- despite the urging of many parents
and some medical professionals who suspect a link between autism and
vaccines. While the federal government has worked to prevent
scientists from studying the adverse effects of vaccines, recommending
research dollars should be spent elsewhere, journalists like Olmsted
and others have stepped in to study the link to autism.[1]''

Let me repeat that for emphasis

"While the federal government has worked to prevent scientists from
studying the adverse effects of vaccines, recommending research
dollars should be spent elsewhere, journalists like Olmsted and others
have stepped in to study the link to autism.[1]''

More from the article

"Olmsted looked for such a group that might establish demonstrative
evidence of whether a link exists, and caught wind of scattered
reports that autism was virtually unheard of among the Amish,
prompting him to begin investigating what has come to be known as the
'Amish anomaly'. The Amish rarely vaccinate children, and Olmsted
found a family doctor in Lancaster County, Pennsylvania, who had
treated thousands of Amish patients. The doctor indicated he had never
seen an Amish person with autism. Based on the national rate of
autism, Olmsted determined there should be 130 Amish children with
autistic syndrome around Lancaster County. After an exhaustive search,
he found four. One had been exposed to high levels of mercury from a
power plant and the others had been vaccinated.[citation needed]

Olmsted then traveled to Amish communities in Ohio and Indiana, with
similar results. In the Amish community around Middlefield, Ohio, the
autism rate was one in 15,000, according to the medical director at a
clinic for special needs children there. In contrast, the Centers for
Disease Control (CDC) has estimated the nationwide prevalence rate at
one in 166.[citation needed]

Olmsted later discovered another large unvaccinated group, thousands
of children cared for by Homefirst Health Services in and around
Chicago, Illinois; according to Homefirst doctors, none of these
children has autism. "We have about 30,000 or 35,000 children that
we've taken care of over the years, and I don't think we have a single
case of autism in children delivered by us who never received
vaccines," said Homefirst's medical director, Dr. Mayer Eisenstein.
[citation needed"

Thanks Vince