Science Forums 2

[Michaelangelica]

What is the biological role of the human male?

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.

In recent years, research has mounted against a virtual police lineup of EDCs, like BPA (in food cans, hard plastic water bottles), phthlates (in soft plastics, cosmetics) and fire retardants (in sofas, computers, flame-resistant clothing). Multiple animal and human studies have linked EDC exposure (during or after fetal development) with a host of hormone-related disorders, like low sperm count, cancer (breast, ovarian, prostate, testicular), congenital malformation of the genitals and even obesity.
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The presence of EDCs in women of child-bearing age is especially worrisome. That is because there is evidence that even minuscule amounts of these chemicals -- levels commonly present in a woman's body -- may disturb fetal brain development during highly sensitive periods of neural development known as windows of vulnerability.
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The US National Toxicology Program has stated that it is concerned about the "effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A."

Furthermore, since multiple different EDCs have the same effect on the developing body, exposure to a variety of EDCs may create a large cumulative stress to the body. (In the CDC study quoted above, 84% of adults tested had more than 6 different phthalates coursing through their bodies...and that study didn't even test for the presence of other EDC, e.g. pesticides, fire retardants, etc.)
. . .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?
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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.

Harvey Karp: Cracking the Autism Riddle: Toxic Chemicals, A Serious Suspect in the Autism Outbreak