Rao Veeramachaneni of Colorado State University said chemical exposure has altered or weakened the reproductive capacity of humans as well as many species of animals.

The biomedical sciences professor told the Rocky Mountain News some chemicals attach themselves to the receptors that are necessary to make various hormones work correctly. By in effect mimicking vital hormones, chemicals can sometimes block the production of the genuine hormones.

The newspaper said Veeramachaneni is currently studying the possible link between common agricultural fungicides and a rising rate of erectile dysfunction in U.S. males.