Good point. In simple terms it means that scientists can take cells from patients who have specific diseases. Then they can reprogram them by treating in a special way to change their properties. This reprogramming process can convert the cells into iPSCs. These iPSCs are unique because they can develop into different types of cells. They are similar to the natural stem cells in our bodies and can transform into different cell types. However, iPSCs are created in a lab by manipulating the patient's natural cells.