We all have different genes, and it makes us who we are. It creates a distinction of our appearance in all aspect. That’s the reason why we differ in height, we have different eye colors, and we have unique skin types, and so on. Our genes hold the answers to our differences. But what if a part of our gene went missing? What if it gets defective? Or what if it mutates and changes into something we don’t know? It can inevitably cause a disease such as cancer and cystic fibrosis. With that, we need to understand what gene therapy is and how it works.