Fertility response to family policy: Insights from Spain’s paternity leave

Purpose This study aims to examine the effect of paternity leave on fertility over time. It exploits the staggered expansion of paternity leave from 2 to 12 weeks to assess how the leave influenced birth rates overall and among specific maternal groups. Design/methodology/approach The authors use national birth records and apply a time series synthetic control framework within a Bayesian Structural Time Series model to construct counterfactual fertility series and estimate the effect of paternity leave over time. As leave entitlement is determined by the child’s date of birth, the authors exploit policy cutoffs to identify variation in exposure. This allows them to track the effects over time and beyond couples who had children immediately around each reform. Additionally, the authors distinguish impacts across maternal groups. Findings While no aggregate effect on fertility is observed, persistent increases in birth rates are found among specific groups. The introduction of a two-week paternity leave led to an 8.4% increase in third births and a doubling of birth rates among employed mothers. These effects remained for at least two years post-reform. Later extensions of paternity leave did not produce further changes in fertility. Originality/value This study provides novel evidence on the limited aggregate impact of paternity leave on fertility and highlights its heterogeneous effects over time across maternal characteristics and birth order. The findings underscore the potential of paternity leave to support fertility through father involvement among employed and non–first-time mothers, suggesting that targeted policies toward these groups could be more effective in promoting fertility.