All humans share many common characteristics, even though we are all completely unique. Similarities are especially noticeable in our biology. We are all made of cells that do all the work we experience as life. Researchers are learning more every day how our genes (genetic factors), where we live and work (environment factors), what we eat and we do (lifestyle factors), and what we believe (cultural factors) affects our common biology making the uniqueness of our lives. Because of the combination of genetic, environmental, lifestyle, and cultural factors, the way any one disease shows up in some people is not the way it shows up in all people. For example, for reasons not yet known, asthma is seen more often in African Americans and generally has more serious symptoms in the African Americans, too. Looking at how the different factors might be causing that means looking at asthma in African Americans compared to others – so studying asthma across the subsets of the population who have similar genetic, environmental, lifestyle, and cultural factors and similar asthma features. By studying in and across subsets of people, and by people identifying their subset through genetic testing and answering environmental, lifestyle, and cultural questions, researchers and health care providers can understand and provide treatment more effective for a person’s unique biology.