In studies using gene modified ES cells and mice, much weight is placed on the production of those fit-for-purpose cells and mice by oneself. Even if they could once be made with some genes, we often experience that other case could not be made after all. What we should do is to repeat the trials with utmost carefulness. To support such a try-and-error experience, a high-level educational program “Try-and-error educational program for the development of novel cell medicine” (tentative title) is planned. The program is composed of, for example, ES cell culture, differentiation induction experiments, gene-modified mouse production, and cell medicine experiments using mice.