The reason I am wary of and do not perpetuate the idea that genes are the major driver of disease is that it leaves people bereft of motivation or reason to change their behavior and improve their condition — and improvement and prevention are indeed possible for the vast majority of health problems, regardless of whether they are linked to genetic inheritance.
Here’s one example:
“Here in the United States, much attention is paid to two rare breast cancer genes, BRCA 1 and BRCA 2, which do in fact confer very high risks for the disease. Genetic tests are available to women who want to learn if they are carriers, and, for many women, there is real value in the knowledge. But even here, genes are not destiny. Among women who are carriers of BRCA 1 and BRCA 2 mutations, 30 percent never go on to develop the disease. Moreover, there are generational differences: of BRCA mutation carriers born before 1940—whose early childhoods predate the dawn of the synthetic chemical industry—only 24 percent developed breast cancer by age fifty. Of those born after 1940, 67 percent had breast cancer by age fifty. These results indicate that even in the exceptional situation in which the inheritance of a single mutated gene strongly predisposes for cancer, environmental factors can modulate risk.”
Steingraber, Sandra (2010-03-23). Living Downstream: An Ecologist’s Personal Investigation of Cancer and the Environment (p. 264).
See also this article by former executive director of Breast Cancer Action, Barbara Brenner: “Genes Are Not Destiny.”