What Is People’s Ideal Number of Children and Do They Achieve It?

Samuel Plach , Bocconi University
Arnstein Aassve, Bocconi University
Letizia Mencarini, Bocconi University

The gap between fertility ideals and realized fertility is central to demographic theory and policy. But the standard measure of fertility ideals, yielding a two-children ideal across high-income countries, suffers from two important limitations restricting its usefulness. First, the traditional measure forces respondents to pick one single number of children, concealing the relative strength of value preferences across child-numbers, thereby inflating the two-child ideal. We instead ask respondents to rate each number of children. Second, because respondents are typically still in childbearing age, the traditional lifetime ideal measure cannot capture the gap between ideals and realized fertility. We therefore also ask respondents about their ideal number of children until their current age, enabling individual-level measurement of their fertility gap. To test these measures, we conducted the Italian Trust-Networks-Fertility (ITNF; 2024) and the Fertility-Motivations (Fer-Mo; 2025) survey (Argentina, Germany, Italy, United States; 2025). We find that while around 60% of respondents select two children in the traditional measure (mean around 2.0), only around 30% of rating points go to two children (mean around 1.8), revealing a flatter distribution and lower ideals overall -- lower in Argentina and Italy than in Germany and the United States. The fertility gap of people in their early 20s is around one child and then narrows over the life course, but less so in Italy, suggesting that barriers to achieving fertility ideals are substantial and emerge early. We will also investigate on individual-level (also using UNFPA data) what drives this fertility gap to inform policy.

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 Presented in Session P2. Families, Fertility, and the Life Course 2