The Changing Trend of Only-Child Family Structures in China: A Simulation Analysis

Under the profound influence of the family planning policy and persistently low fertility, the number of only children has increased rapidly, giving rise to only-child families that face distinctive social risks and challenges. However, how the development of only-child family structures has changed over the past four decades remains unclear. Based on the national population census conducted between 1982 to 2020, employing life tables and probabilistic methods, we analyze changing trends of only-child family structure indicators by death sequence in China, and explore the effects of parental age at childbirth and spousal age gap on these indicators. The findings show the likelihood of losing a child declined steadily, the ages of both the child and parents at child’s death were postponed. When parents predecease their child, child’s age at their parental death has risen to over 60 years, with the duration the child survived alone remaining stable. Age-specific probabilities by death sequence indicate parents typically die when the child is over 63, shidu families tend to become one-person households after the 60th year since childbirth. The ultimate cumulative probabilities of the death order father-mother-child is the highest (51.63%). In shidu families, the ultimate cumulative probability for the death order father-child-mother is the highest (6.50%), while mother-child-father has the lowest (2.56%). As parental age at childbirth increases, the ultimate cumulative probabilities of each death orders in shidu families decline, the child’s age at death decreases, and the duration parent survives alone remains stable. However, if both parents predecease the child, the ultimate cumulative probabilities rise, the child’s age at their parental death decreases, and the duration the child survives alone increases. Additionally, these indicators are also influenced by spousal age gap. The findings highlight the need for differentiated support policies tailored to the evolving dynamics of only-child family structures.