Birth Control Hormones Change Fishes' Sex
"What we see in the fish downstream is as if they are taking birth control pills," Norris said. The female fish — both the transsexuals and the original girls — had smaller-than-average ovaries. The remaining males produced less sperm, showing the water effluent also has contraceptive effects, he said. The chemicals are believed to come from excreted birth-control hormones, natural female hormones and detergents flushed down toilets and drains.