The Influence of relatives on the timing of first birth: evidence from a low fertility population

Paul Mathews, London School of Economics and Political Science (LSE)
Rebecca Sear, London School of Economics and Political Science (LSE)

There has been considerable interest in demography over the last two decades in the influence of social networks on fertility behaviour. Relatively little attention has been given to the content of these social networks. Anthropologists have recently become interested in how relatives influence fertility behaviour, but have so far focussed on measuring the effects of relatives on fertility in natural fertility populations. Here, we test whether the presence of kin in her social network influences the risk of a woman’s first birth in the UK. As a secondary objective we compare the effects of relatives’ geographic proximity and frequency of contact. We use six waves of the British Household Panel Study, a longitudinal dataset collected during the 1990s-2000s. Discrete-time event history analysis is undertaken to determine whether the degree of ‘kin orientation’ influences the risk of first birth for women. Kin orientation is operationalised as the number of relatives who are within a woman’s three closest non-household friends. Our results show that greater kin orientation significantly increases the risk of first birth, controlling for age, household composition and socio-economic status, suggesting that women who have close ties with their kin have earlier first births than those with looser kin ties. We further determined that the effect is strongest when those relatives in the close social network both live within 50 miles and are contacted frequently. This study suggests that the content of social networks is important, and that relatives influence reproduction even in a modern low fertility context.