The Swedish Kinship Universe – A demographic account of the number of children, parents, siblings, grandchildren, grandparents, aunts/uncles, nieces/nephews, and cousins using national population registers

We know surprisingly little about the demography of human kinship. In the current study, we give a demographic account of the kinship networks of individuals in 2018 in Sweden across sex and cohort. We used administrative register data of the entire Swedish population in order to provide the first kinship enumeration for a complete population based on empirical data. We created ego-focused kinship networks of children, parents, siblings, grandchildren, grandparents, aunts/uncles, nieces/nephews, and cousins. We show both the average number of kin of different types and the distribution of the number of kin as well as how dispersion has changed over time. We show trends for matrilineal and patrilineal kin and also show differences in the kinship structure arising from fertility with more than one childbearing partner, such as half siblings. The results demonstrate extensive variability as well as homogeneity in kinship structure. We discuss our findings in the context of other methods to estimate kinship.