Union instability and fertility : a microsimulation model for Italy and Great Britain

Family dynamics are changing in Europe, but only few studies investigate how cohort completed fertility is affected by partnership behaviours and how this has changed over time. We use microsimulation techniques to investigate the effect of the increasing prevalence of union dissolution on completed fertility levels in Italy and Great Britain, two countries with very different systems of value. We find that the net effect of union instability is to decrease fertility (by about 0.5 children for Italian and 0.2 to 0.4 children for British cohorts) but the magnitude of the difference depends on the timing of union formation and separation. As expected, re-partnering produces more children in new partnerships if the separation occurs earlier. Nonetheless, it is only if separation takes place after the second birth and if all women re-partner that additional childbearing would almost compensate for births lost due to union disruption.