Born Once - Die Once


Towards a Transdisciplinary Demographic Theory of Birth and Death Trajectories

Welcome to the Born Once - Die Once project website!

📌

Call for Papers Now Closed (but keep reading)

Thank you for your interest and for all the high-quality submissions. We are looking forward to welcoming participants to the workshop. We are currently reviewing submissions and will contact applicants by January 15th .

In addition, the workshop reserves a small degree of flexibility for late applications in exceptional cases, where the proposed contribution aligns particularly closely with the workshop theme. Scholars with a strong thematic match are welcome to contact us directly at b1d1@sdu.dk .

View more about the workshop →

The project

Birth and death are key drivers of population change. While mortality follows well-established regularities —eight in particular— fertility remains harder to forecast, and this uncertainty leads to much of the error in population projections. More information can help reduce uncertainty and might be hidden in currently unexplored regularities of fertility. To find those patterns, Born Once – Die Once asks a simple, generative question: do the same regularities that organize death also structure birth?

Early evidence suggests they might. The Gompertz law’s exponential rise in mortality risk appears to have a parallel in childbirth, and the long-run linear increase in record life expectancy seems mirrored by a linear rise in record “birth expectancy.” Building on these clues, the project adapts formal demographic models from mortality to fertility, tests the suite of mortality regularities on birth patterns, and develops improved tools for modeling population renewal.

We then extend this mirrored approach from individuals to collectives. Couples, families, and households are treated as “social individuals” that form (are “born”) and dissolve (or “die”). By analyzing formation and dissolution data, we seek general rules that describe these trajectories over time and across contexts.

Our goal is a shared theoretical framework for birth and death—across systems and scales—that sharpens forecasts, unifies concepts, and equips researchers with a practical toolbox. By aligning the study of formation, dissolution, renewal, and aging, Born Once – Die Once aims to strengthen the foundations of the population sciences and open a new, transdisciplinary line of inquiry.

ERC Logo SDU Logo

Funded by the European Union (ERC, Born Once - Die Once, 101043983). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.

Last updated: December 2025