What's the worth of having a single CS teacher program aimed at teachers with heterogeneous profiles?

There is consensus regarding the relevance of including Computer Science (CS) in official school curricula. However, this discipline cannot be taught on a large scale until there are enough trained teachers who can effectively lead a class. In this article, we discuss the results of a 400-hour teacher training program conducted in Argentina aimed at K-12 teachers with no CS background. The only requirement to sign up was to be an in-service teacher, and therefore there were a plethora of different teacher profiles that attended the courses. Our research aims at understanding whether a single teacher training program can be effective in teaching CS contents and specific pedagogy to teachers with very heterogeneous profiles. Also, we investigate what teachers expect to do with the contents they learn. To assess these questions anonymous examinations and questionnaires were given and interviews were conducted with course attendees. Even though the majority reached the expected minimum bar regarding CS contents and pedagogy, significant differences appear in their self-perception as regards career opportunities in CS teaching. Our conclusion is that carrying out CS teacher training for a broad spectrum of profiles may be effective for promoting CS contents. However, if the goal is to boost teachers' confidence in teaching a CS subject, then having a program which focuses on a more restricted selection of profiles would be a better strategy.