We propose a formal meta-theory for the generation and development of mathematical theories in terms of minimal structural steps. A mathematical theory is represented as a first-order presentation, and theory growth is modeled by elementary conservative extensions that add one structural primitive at a time. We isolate three major families of structural primitives: algebraic, topological, and order-theoretic. These are not claimed to exhaust all mathematical content in an ontological sense; rather, they provide a robust and mathematically precise decomposition scheme for a large class of formal theory-building operations. We prove that every finite definitional extension of a many-sorted first-order theory factors into a finite sequence of minimal steps, each of which is structural of one of the three types. We then define a structural profile and a complexity measure for theories, prove its basic invariance and additivity properties, and show how the interaction of different structural families produces new nontrivial statements by enabling new definable configurations. The resulting framework gives a precise mathematical language for discussing the generation of theories, the locality of theory expansion, and the role of structural sensitivity in formal innovation.