(jeh-NEH-tik) Having to do with genes. Most genes are sequences of DNA that contain information for making specific RNA molecules or proteins that perform important functions in a cell. The information in genes is passed down from parent to child. Sometimes, certain changes in genes can affect a person’s risk of disease, such as cancer. These changes may be inherited or they may occur with age or exposure to environmental factors, such as diet, exercise, drugs, and chemicals.