Incorrect. Most cancers and most other major illnesses are caused by environmental and lifestyle factors. One rare form of colon cancer is genetic (if by "genetic" you mean "heritable"), in that it's passed down from parents to children. All cancer is "genetic" in that it results from damage to genes in the cells of the affected organ. Inherited genes create tendencies toward the development of some diseases, but it's environmental and lifestyle factors that result in those tendencies being realized. A genetic tendency to high cholesterol or high triglycerides does not "cause" heart disease - a diet and/or lifestyle that causes that tendency to be realized does. Calling disease "genetic" helps relieve people of personal responsibility for their lifestyle choices, and social responsibility for environmental factors. I have no doubt that my cancer was caused by a sedentary lifestyle, poor diet choices, stress, and maybe some environmental factors, not by my genes