How do new teachers become confident and competent while they are interns in inner-city neighborhood schools challenged by many problems, often associated with economic shortfalls and cultural differences between the students and their teachers? Many science teacher education programs place a lot of emphasis on the planning stages of curriculum. But considerable discrepancies emerge between planned and lived curriculum, particularly in inner-city, comprehensive high schools, and especially in classrooms that honor student interests and culture as starting points for learning. Previous research showed that coteaching provides opportunities for learning to teach even though the lived curriculum emerges often in unpredictable ways from the dialectic of collective (teacher and students) agency and structure. The present study allowed us to understand the underlying processes: the presence of a coteacher increases access to social and material resources, and thereby increases opportunities for actions that otherwise would not occur. Greater teaching opportunities provide newcomers with greater opportunities of learning to teach.