Simulating the Historical and Future Availability of Living Ancestors throughout the Life Course, 1751–2100

Liliana Calderón-Bernal , Max Planck Institute for Demographic Research

How often do people have living parents, grandparents, and great-grandparents throughout their life courses, and how has this changed over time? Declining mortality, increasing longevity and falling fertility have transformed kinship networks over the past few centuries. These demographic changes have led to an increase in the number of living generations, and a decrease in the number of members in each generation, which has transformed the potential for intergenerational relationships throughout the life course. This research uses SOCSIM demographic microsimulation to reconstruct and project the availability of parents, grandparents, and great-grandparents throughout the life courses of individuals born between 1751 and 2000. A large microsimulation for Sweden over 1751–2100 is run using age-specific fertility and mortality rates obtained from the Human Fertility Collection, the Human Fertility Database, the Human Mortality Database, and the World Population Prospects 2024. This produces a synthetic population with fully recorded information on demographic events and kinship networks, which allows calculation of two types of cohort-level measures: mean numbers of parents, grandparents, and great-grandparents alive at birth, and lifetime overlap with each ancestor. Following Song and Mare (2019) and Caswell and Vries (2025), overlap with ancestors is operationalised as: years with at least one living ancestor of a given type, aggregate person years of overlap summed across all ancestors, and mean overlap per ancestor. By analysing patterns of ancestral availability by age and cohort over time, this study sheds light on how demographic change has reshaped opportunities for contact, support, and caregiving across generations.

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 Presented in Session 90. Kin Availability and Complex Networks in Ageing Populations