Yoga is much more than an exercise program or stretching. Yoga is living life to overcome the human condition of suffering. In fact you could say that everyone does yoga to some degree or another. Yoga recognizes that each individual is unique and there are different practices to meet various needs.
Yoga is for anyone that wants to live life better than they are living it now. Yoga transcends all limitations of income level, education, race, and age to provide the opportunity for everyone to live in their unbounded nature.
Yoga is not a religion, there is no dogma and excludes no one, but provides the roots of morality which most religions adopted. Connecting with your source of creation and living in the moment is the spiritual aspect of yoga.