According to a study published in the American journal Environmental Health Perspectives, only about a third of babies born on the reserve between 1999 and 2003 were male. Going back to include another five years, only 41 per cent of babies born in the decade were boys. The ratio is normally something closer to 50:50.What's could be causing the problem? The study notes that there is increasing evidence that the human live birth sex ratio can be changed by a number of environmental and occupational chemical exposures. For example, fewer births of boy babies have occurred in populations exposed to dioxin, mercury, pesticides, polychlorinated biphenyls (PCBs), and parental smoking. According to many experts, the cause may be a class of chemicals called endocrine-disrupters that can influence the sex ratio by affecting the hormonal balance of the parents, or by killing fetuses of a certain gender in utero.
Exposure to chemicals is common in that area. According to Constanze Mackenzie, the fourth-year medical student at the University of Ottawa who led the study
"The community is located right in the centre of a number of large petrochemical and chemical industrial plants, so it is suspected they do have multiple exposures to environmental contaminants," said MacKenzie.">"The community is located right in the centre of a number of large petrochemical and chemical industrial plants, so it is suspected they do have multiple exposures to environmental contaminants," said MacKenzie.The Canadian Chemical Producers' Association suggested more research.
She added there is ongoing research in the area that shows similar changes in sex ratios and the reproductive ability of local wildlife.
GAO, NY Times & Wall St Journal: US Chemical Policy Needs Fixing, August 3, 2005