Misconceptions About Environmental Pollution, Pesticides and the Causes of Cancer

Policy Reports | Energy and Natural Resources

No. 214
Sunday, March 01, 1998
by Bruce N. Ames and Lois Swirsky Gold

Misconception #9: Pesticides and Other Synthetic Chemicals Are Disrupting Hormones

"Even if sperm counts were declining, there are many more likely causes, such as smoking and diet."

Synthetic hormone mimics have become an environmental issue. Hormonal factors are important in cancer, as mentioned in Misconception #2. The 1996 book Our Stolen Future73 claims that traces of synthetic chemicals, such as pesticides with weak hormonal activity, may contribute to cancer and reduce sperm counts. The book ignores the fact that our normal diet contains natural chemicals that have estrogenic activity millions of times higher than that due to the traces of synthetic estrogenic chemicals74 and that lifestyle factors can markedly change the levels of endogenous hormones [see Misconception #2]. The low levels of exposure to residues of industrial chemicals in humans are toxicologically implausible as a significant cause of cancer or of reproductive abnormalities, especially when compared to the natural background.75 In addition, it has not been shown convincingly that sperm counts are declining,76 and even if they were, there are many more likely causes, such as smoking and diet.

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