There is research supporting the theory that lifestyle and environment can change how our genes express themselves. Studies show that the genetics of identical twins can change significantly due to lifestyle choices.
The implications are that making healthy eating choices, exercising, clean air and water, and having parents that made the same choices can have a dramatic effect. Do it for yourself and do it for those children you are planning to have.
Check out this Q&A link. Evidence shows that smoking and exposure to chemicals affects our genetic expression. Take care of those genes!