When Politics Aligns: The Effect of Party-in-Power Congruence on Fertility in the UK

Lukasz Baszczak , University of Warsaw
Ewa Weychert, University of Warsaw

We investigate how political context shapes fertility behaviour in the United Kingdom. We argue that alignment between individuals' political identity, and whether one’s preferred party wins elections and governs, plays an important role in shaping narratives about the future and, consequently, decisions related to family formation. Using panel data from the UK Household Longitudinal Study (UKHLS, 1991–2019), we examine how alignment between individuals' partisan preferences and the ruling party affects the monthly probability of conception. Applying mixed-effects complementary log–log regression models with standard demographic and socioeconomic controls, we find that Conservative Party supporters are more likely to conceive a child during periods when their party is in power, while no such effect is observed among Labour voters. A difference-in-differences analysis of all general elections between 1991 and 2019 further shows that the 2010 election, which returned the Conservatives to power, was followed by an increase in conception likelihood among Conservative supporters compared to the pre-election period, whereas no comparable effects were found for other elections or the 2016 Brexit referendum, or for Labour voters. These findings suggest that political alignment between citizens and government is one of the factors influencing fertility behaviour. The results contribute to the growing literature on political polarization and demographic decision-making, highlighting the role of subjective expectations regarding the domestic political situation and stability, and identity-based narratives in shaping reproductive behaviour.

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 Presented in Session P1. Families, Fertility, and the Life Course 1