[The National Institute of Environmental Health Sciences wrote:]

“We’re struggling to look at where genetics and the environment interact in the human cell, causing a molecule to change that starts a kind of chain reaction leading to disease. Scientists liken the changes to a cascade—a series of ever-larger waterfalls of cellular changes—that may lead to cancer, Parkinson’s, arthritis, heart disease or other diseases. Though we still do not understand the root causes of many of these serious chronic diseases, we suspect they can be caused or triggered by chemicals and other environmental exposures from years before.

qtd. in The Hundred-Year Lie by Randall Fitzgerald,  pg. 31