Antiandrogens, or androgen antagonists, first discovered in the 1960s, prevent androgens from expressing their biological effects on responsive tissues. Antiandrogens alter the androgen pathway by blocking the appropriate receptors, competing for binding sites on the cell's surface, or affecting androgen production. Antiandrogens can be prescribed to treat an array of diseases and disorders. In men, antiandrogens are most frequently used to treat prostate cancer. In women, antiandrogens are used to decrease levels of male hormones causing symptoms of hyperandrogenism. Antiandrogens present in the environment have become a topic of concern. Many industrial chemicals, pesticides and insecticides exhibit antiandrogenic effects. Certain plant species have also been found to produce antiandrogens. Environmental antiandrogens can have harmful effects on reproductive organ development in fetuses exposed in utero as well as their offspring.