It didn’t require many hours in the university library to learn that bladder cancer is considered a quintessential environmental cancer, meaning that more evidence exists for a link between toxic chemical exposure and bladder cancer risk than for almost any other kind of cancer, with data going back a hundred years. […]

I also started a collection of pamphlets on bladder cancer, gathered from  the various waiting rooms and hospitals where I spent time. I noticed that they seldom contained the words “carcinogen” or “environment.” (More on these in Chapter Twelve.) Nor were these words used anymore in conversations I had with my various health care providers. There seemed to be a disconnect between the evidence that medical researchers had compiled about the environmental origins of bladder cancer and what patients heard about that evidence. To judge by the medical intake forms, the more relevant variable was genetics:  was asked again and again about my family medical history. I was happy enough to provide it. There is a lot of cancer in my family. My mother was diagnosed with breast cancer at age 44. I have uncles with colon cancer, prostate cancer, stromal cancer. My aunt died of the same kind of bladder cancer–transitional cell carcinoma–that I had.

But here’s the punch line to my family story: I am adopted.

And when I looked at the literature on cancer among adoptee, I learned that, in fact, the chance of an adopted person dying of cancer is more closely related to whether or not her adoptive parents had died of cancer and far less related to whether or not her biological parents had met such a fate. What runs in families does not necessarily run in genes.

Sandra Steingraber. Living Downstream: An Ecologist’s Personal Investigation of Cancer and the Environment  (Foreword to Second Edition). Da Capo Press. Kindle Edition.