Background: Complex extended families are common in rural sub-Saharan Africa. Relationships between family members take on a wide range of forms (polygamy, classificatory kinship system). However, the complexity of children's family unit and changes in it are not well taken into account by quantitative surveys.

Objective: Our paper brings together traditional demographic perspectives, anthropological and genealogical approaches, to analyze children's kinship networks and how they change over time. By documenting who is present in a child's network and who remains there over time, our approach aims to generate new insights into the context of child socialisation.

Methods: Using genealogical data, coupled with results from a follow-up survey conducted in rural Mali, we define the set of kinship ties that connect each child to other members of his domestic group and measure the turnover in children’s family environment.

Results: Children grow up surrounded by complex families whose boundaries extend well beyond parents, siblings, and close relatives. Moreover, this environment constantly changes. In the space of five years, 50% of the people in a child's relational network are replaced.

Contribution: Relationship between family dynamics and children's socialisation have been largely ignored in demographic studies. This article shows that longitudinal data can shed light on the impact on children of family dynamics.