"Genetics" have become a scapegoat for all sorts of diseases - obesity, cardiovascular problems, digestive problems, allergies, arthritis - basically, if you can think of a disease, it is likely you have heard someone refer to it having a genetic link. Genes are really just the coding of our individual bodies. Of course, some of this information is passed from generation-to-generation. This is obvious when comparing a newborn child to his/her parents.
While it is possible to share some of this "code" for diseases, in a vast majority of cases your genes do not define your performance in life. Just because your father and your grandfather have had histories of heart disease, does not mean you have to carry the torch like an Olympian. Most illnesses that can be chalked up to genes and "cured" by a doctors prescription are entirely avoidable through simple lifestyle changes.