Carbofuran is an endocrine disruptor and a probable reproduction/development intoxicant. At low-level exposures, carbofuran may cause transient alterations in the concentration of hormones. These alterations may consequently lead to serious reproductive problems following repeated exposure. When exposed "in utero" or during lactation, a decrease in sperm motility and sperm count along with an increase in percent abnormal sperm was observed in rats at 0.4 mg/kg dose level. In one study, the exposure of rats to sublethal amounts of carbofuran decreased testosterone by 88%, while the levels of progesterone, cortisol, and estradiol were significantly increased (1279%, 202%, and 150%, respectively).