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Declining sex rations

There has been a statistically significant decline in the ratio of male to female births in several industrialized countries, including Denmark, the Netherlands, Canada, and the United States, that cannot be attributed to known factors. Parallel declines have also been reported in Sweden, Germany, Norway and Finland. Birth defects of the male reproductive tract and diseases such as testicular cancer have also increased in some industrialized countries, possibly associated with exposure to certain environmental compounds. The downward trends in sex ratio may not have a benign cause. Occupational and community exposures to pesticides and dioxin have been linked with declines in sex ratio in a number of studies. The reduction in the proportion of males born may be a sentinel health indicator that some, as yet, unrecognized environmental health hazards are affecting both sex ratio and the other unexplained defects in male reproduction (Davis, Gottlieb and Stampnitzky, 1998).


Davis, Devra L., Michelle B. Gottlieb, and Julie R. Stampnitzky. 1998. "Reduced Ratio of Male to Female Births in Several Industrial Countries: A Sentinel Health Indicator?". Journal of the American Medical Association, 1 April 1998.


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