Last year, scientists thought they'd found out why female fish in some paper-mill–polluted Florida rivers look like males (SN: 1/6/01, p. 8: Macho Waters). They'd discovered androstenedione, a male hormone and a precursor to testosterone, in the water.
Androstenedione probably formed from pollutants and then became concentrated enough to affect the fish, the researchers said.
Now, others are questioning whether androstenedione is the gender-bending agent. Gerald T. Ankley of the Environmental Protection Agency's National Health and Environmental Effects Laboratory in Duluth, Minn., and his coworkers analyzed polluted water from Florida's Fenholloway River, as researchers had done in the earlier experiments.