Male Births: Decline In The US And Japan

http://www.sciencedaily.com/releases/2007/04/070409115759.htm

A study published in this week's online edition of Environmental Health Perspectives reports that during the past thirty years, the number of male births has decreased each year in the U.S. and Japan. In a review of all births in both countries, the University of Pittsburgh-led study found significantly fewer boys being born relative to girls in the U.S. and Japan, and that an increasing proportion of fetuses that die are male. They note that the decline in births is equivalent to 135,000 fewer white males in the U.S. and 127,000 fewer males in Japan over the past three decades and suggest that environmental factors are one explanation for these trends.

... "Given the importance of reproduction for the health of any species, the trends we observed in the U.S. and Japan merit concern," added Dr. Davis. "In light of our findings, more detailed studies should be carried out that examine sex ratio in smaller groups with defined exposures as a potential indicator of environmental contamination."