This article focuses on student teachers' professional identity formation inspired by the tension between two layman points of view namely: being born as a teacher (i.e. based on demographics and personality traits) and becoming a teacher (i.e. based on experience). Besides demographics, personality traits and experience, the teacher preparation context is considered as a crucial aspect in professional identity formation as well. The authors adopted a multiple theoretical approach to guide the empirical study. Using hierarchical regression analyses the relative influences of demographics and personality traits, context variables and teacher education variables on professional identity variables are explored. (Contains 4 tables and 2 figures.)