A lesser-known theory on autism triggers: endocrine disrupting chemicals (EDCs)?

July 4, 11:17 AMSF Education ExaminerCaroline Grannan

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Special Education Examiner Robin Hansen alerts readers to a commentary (by high-visibility UCLA pediatrician Dr. Harvey Karp, in the Huffington Post) on a theory about possible autism causes. Karp writes:

One group of substances of particular concern is a ubiquitous family of hormone twisting compounds, known as endocrine disrupting chemicals (EDCs). These substances are the focus of intense scrutiny because: 1) they're found in every home in America 2) they're increasingly linked to human disease 3) our exposure to them has risen in parallel with the surge in autism diagnoses and 4) they may theoretically affect the developing fetal brain.

... Our increasing exposure to EDCs lends support to a new hypothesis about the cause of autism, called the "extreme male theory." This theory, proposed by Dr. Simon Baron-Cohen and colleagues, speculates that autism is caused by something changing a fetus' hormonal balance that then leads to over-masculinization of the developing brain.
Could that "something" be the slurry of hormone-altering chemicals we're exposed to every day? Are EDCs the reason autism-type disorders are 4-9 times more common in boys? (Vaccine side effects never show such lopsided impact on boys versus girls...a glaring fact that is totally ignored by those promoting the vaccine theory of autism.)
The "extreme male theory" has been supported by two interesting bits of evidence: 1) fetuses with slightly elevated levels of testosterone grow up acting extra-male (more interested in things than people, slow language development, etc.); 2) children with autism -- boys and girls -- show extra-male characteristics (e.g. poor social ability, language delay).
Here is where the very interesting link to EDCs comes into play: EDCs often act as weak estrogens and estrogen feminizines the body, but in a fetus' developing brain estrogen actually has the opposite effect...it causes masculinization.
For now, these ideas are just interesting theories, but the evidence is concerning. We urgently need more research to discover whether EDCs, or other chemicals, are linked to the worldwide rise in autism. Fortunately, on that front, there is very good news to report. Thanks to a dedicated group of pediatricians -- members of groups like the AAP and CDC -- the National Children's Study (NCS) was launched in January 2009.
Originally designed during the Clinton presidency, the NCS survived 8 years of Bush administration attempts to defund and demolish it. But today, the new administration has committed over $3 billion to carrying it out.

This is not at all my area of expertise, but the debate over whether vaccines may trigger autism troubles me, and Dr. Karp's point that there's no scientific reason that would affect so many more boys than girls is intriguing.
 

The Huffington Post commentary prompted a series of angry and abusive retorts aimed at Karp. I Googled a little more to get an idea of whether he's famously controversial; the first anti-Karp commentary I came across started by calling him an "arrogant (epithet)" and claimed he's lying about being employed by UCLA. Since it was pretty easy to confirm his connection with UCLA, that didn't help his critics' credibility much. I can't get a read on whether this is the "autism is caused by vaccines" faction hitting back at a voice they disagree with or if there are other issues in play. In any case, it seemed worth calling attention to the theory about EDCs and following the research.