When a gene in the human body goes bad, it can cause illness and disease. Scientists have been working for decades to develop therapies to address faulty genes. In the U.S. gene therapy has been approved as a treatment for illnesses such as cancer, hemophilia, AIDS. However, as researchers explore treatment possibilities. The ethics and costs of such treatments remain a concern. A new book aims to provide an overview of the state of gene therapy development which is the focus of this episode of Stat+Stories with guests Avery McIntosh and Oleksandr Sverdlov. Dr. McIntosh is a drug developer working in rare diseases at Pfizer. He has managed teams of statisticians across study phases and in a variety of drug types and disease areas, including neurology, ophthalmology, infectious disease/ global health, hematology, and oncology. He has published peer-reviewed articles on various topics in drug development and biostatistics, including development of cell and gene therapies and qualification of digital endpoints in neurological diseases. Dr. Sverdlov is a Neuroscience Disease Area Statistical Lead at Novartis. He has been actively involved in methodological research and applications of innovative statistical approaches in drug development. He has co-authored over forty refereed articles, edited two monographs, and co-authored a book ``Mathematical and Statistical Skills in the Biopharmaceutical Industry: A Pragmatic Approach''. His most recent work involves design and analysis of clinical trials evaluating novel digital technologies.