The research, published in the journal Aquatic Toxicology, reports the findings of a study of 16 different fish species between 1995 and 2004.
The study looked at fish in the Apalachicola, Colorado, Columbia, Mobile, Mississippi, Pee Dee, Rio Grande, Savannah, and Yukon River basins.
The bass were found to be the most commonly intersexed.
Sue Haseltine, associate director for biology at the US Geological Survey, told USA Today that the study reveals the prevalence of intersex is more widespread than anyone anticipated.
And she called for more studies into hormonal changes in fish and environmental factors.
Study Finds Prevalence of Hermaphrodite Fish
US - Research has found high levels of sexual defects in smallmouth and largemouth bass, with many having both male and female characteristics.
