Background: The life-course approach as a methodological framework for the empirical analysis of longitudinal individual-level data has fundamentally changed the agenda of demographic research. However, these methodological innovations have not been paralleled by a similarly successful theoretical integration in the life-course field.

Objective: We aim to show that the life course is an indispensable framework for demographic research. Social forces, both structural and cultural, are articulated in the life-course dimension, and the individuals who act under their influence conceive of their actions in life-course terms. Thus, theories of fertility need to be set in these terms as well.

Results: In substantive terms, the life-course approach promises to integrate the extra- and intra-individual levels of relevant processes in a system of interdependent dynamics that unfolds over time; to conceptualize fertility and family formation as part of a multidimensional process of welfare production which requires complex decisions on the proper allocation of time and resources to the different life domains; to examine how cultural scripts and institutional programs shape and interact with intentions and preferences; and to highlight the impact of the past and anticipation of the future as a framework for the number, timing and spacing of births. In methodological terms, the life-course approach requires a shift in the efforts to identify complex causal mechanisms in empirical research.

Conclusions: Even though the life-course approach still lacks the status of a systematic theory, several hypotheses can already be drawn from it, which extend the scope of fertility research, and demonstrate it to be an indispensable framework for studying fertility decisions.