Life-cycle exposure of fathead minnows (Pimephales promelas) to an ethinylestradiol concentration below 1 ng/L reduces egg fertilization success and demasculinizes males.

Forty-eight hours after fertilization, fathead minnow (Pimephales promelas) eggs were exposed to the synthetic estrogen 17alpha-ethinylestradiol (EE2) at nominal concentrations of 0.32 and 0.96 ng/L and measured concentrations of 3.