A small native community living in the shadows of Sarnia's chemical valley has had an unusual distinction: Researchers believe it has one of the most skewed sex ratios in the world. For reasons that are not known, the percentage of male births in the community, known as the Aamjiwnaang First Nation, began to fall precipitously in the mid-1990s. By 2003, newborn girls outnumbered boys by about 2 to 1. It was a dramatic reversal of what is considered normal in human populations - a modest excess of male births - the trend that had previously prevailed on the reserve.
New figures on the reserve's birth rates presented yesterday at a conference in Sarnia indicate that the extent of the male birth dearth may be diminishing, although only slightly. In 2004, equal numbers of boys and girls were born, the first time since the mid-1990s that the reserve has had a birth ratio approaching normal. The next year, however, the number of baby girls once again exceeded boys. Figures for 2006 are not yet available.
Margaret Keith, one of the researchers who compiled the data, cautioned in an interview that annual figures comparing the number of male to female births in a small population can be volatile, but the longer-term trend to fewer male births seems to be persisting.
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She said that over the past five years, only 42 per cent of births have been male, well under the national figure of 51.2 per cent. While she said she hopes the birth data will revert to normal "to me, it looks like the trend is still there." The unusual birth ratio in the community, which has major petrochemical plants on two sides and is downwind of high-polluting U.S. power plants, has attracted worldwide attention. There is an international trend observed in many industrialized countries, including Canada, the United States, the Netherlands and Japan, to lower-than-expected percentages of male births, although the drop in large populations is very slight.
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