Our emotions are not who we are just as our thoughts are not who we are. How we choose to respond to them or for that matter not to respond to them is closer to who we are. Our thoughts and emotions do represent us and is how others experience us or for that matter how we experience ourselves. They are a cumulative result of all the choices we have ever made. However, as long as we are alive and thus have the power to choose we also have the power to cancel the impact of all that we have come to be.
"Today, DNA testing involves analyzing multiple genes to determine the risk of developing specific diseases or disorders, with the more common diseases consisting of heart disease and cancer. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder. Many of the risks associated with genetic testing involve the emotional, social, or financial consequences of the test results. People may feel angry, depressed, anxious, or guilty about their results. The possibility of genetic discrimination in employment or insurance is also a concern. Other risks include accidental findings—a discovery of some possible problem found while looking for something else." The critical issue as I see is having to deal with life-long anxiety if one discovers one major illness or another. -source: Wikipedia