"Government scientists figure that one out of five male black bass in American river basins have egg cells growing inside their sexual organs, a sign of how widespread fish feminizing has become.

The findings come from the U.S. Geological Survey in its first comprehensive examination of intersex fish in America, a problem linked to women's birth control pills and other hormone treatments that seep into rivers. Sporadic reports of feminized fish have been reported for a few years.

The agency looked at past data from nine river basins -- covering about two-thirds of the country -- and found that about 6 percent of the nearly 1,500 male fish had a bit of female in them. The study looked at 16 different species, with most not affected.

But the fish most feminized are two of the most sought-after freshwater sportfish: the largemouth and smallmouth, which are part of the black bass family."

Seth Borenstein reports for the Associated Press September 14, 2009. [2]