Industry blamed for massive dive in male birth rate
Chippewas living in the shadow of industrial plants in Ontario have reported a worrying drop in the number of male births within the community.
Globally slightly more male children are born than female, the balance is, as might be expected, roughly half and half with the ratio usually somewhere around 51% to 49%.
While regional variations do exist around the world, Canada follows the trend, with the national male birth rate at 51.2%.
The Chippewas community near Sarnia, however, shows a startling divergence from the national average, with only one in three babies born male in recent years.
Research into the discrepancy was led by Constanze Mackenzie from the University of Ottawa, who concluded that the most likely explanation for the plummeting rate of baby boy births was the proximity of the settlement to a host of heavy industry plants.
The report was published in Environmental Health magazine.
"The trend in the proportion of male live births of the Aamjiwnaang First Nation has been declining continuously from the early 1990's to 2003, from an apparently stable sex ratio prior to this time," the researchers wrote in their study.
"This community is situated immediately adjacent to several large petrochemical, polymer, and chemical industrial plants.
"Although there are several potential factors that could be contributing to the observed decrease in sex ratio of the Aamjiwnaang First Nation, the close proximity of this community to a large aggregation of industries, and potential exposures to compounds that may influence sex ratios warrants further assessment into the types of chemical exposures for this population."
The effects of endocrine disruptors, or 'gender bender' chemicals, have been well recorded in the animal kingdom, but their direct impact on human development is less understood.
The Sarnia case is likely to shed some light on the matter but the effects of individual substances could be a difficult to unravel, as the population is likely being exposed to a cocktail of chemicals rather than a single compound.
Meanwhile, the problem persists for the Chippewas and appears to be getting worse.
20 years ago, the gender balance seemed normal in Sarnia.
Over the past 15 years, the imbalance has grown and is now at its greatest level since concerns were raised, with just 34.8% of births resulting in male children between 1999 and 2003.
A community health survey is currently underway to gather more information about the health of the Aamjiwnaang community and to provide additional information about the factors that could be contributing to the problem. By Sam Bond