Until a few years ago, my father was the only person in my family who’d ever had cancer. In 1997, he was diagnosed with mesothelioma, which is almost always caused by exposure to asbestos.

My dad developed the disease in his lungs after working in the electrical services industry for 20 years. By the time he was diagnosed, the cancer had already spread to his brain. My father died of complications of mesothelioma in 1999, at age...