The advances in biomedical research and its therapeutic applications are the subject of controversial discussions. A group of biologists, lawyers, medical professionals, philosophers, and theologians has taken on the task of making these developments transparent to a broader public and reflecting on their ethical assessment. This has resulted in this book, which serves as a guide regarding the latest developments in gene and stem cell research as well as their medical applications. To this end, the scientific foundations and processes are presented, potential benefits and risks are explained, and an ethical evaluation is provided. The core of the book features an ethical tier model, in which the possible medical applications of gene and cell technology are exemplarily illustrated across four stages of medical application.