From investigations based on the human genome and the environmental genome programs, genetic basis for individual differences in response to environmental mutagens is being characterized. Inheritance of variant versions of certain polymorphic genes is frequently associated with the development of environmental disease, such as lung cancer from cigarette smoking. Inheritance of these alleles may also affect the quality of life such as longevity. Evidence in support of these possibilities is presented. It is obvious that through the understanding of susceptibility, more precise disease prevention strategies can be implemented which will not only reduce the disease burden but also improve the quality of life.