Ryohei Mogi , University of Oxford
Peter McDonald, University of Melbourne
Vladimir Canudas-Romo, Australian National University
The age at entering motherhood has increased largely in the high-income countries since 1970s. As the fecundability of both males and females depends on age, known as the “biological fertility clock”, postponement of childbirth to later ages increases the chance of remaining childless or having a low parity. However, parallel to the physical barriers to bear children, there are social constraints to fertility, among the most important being having a partner and forming a union. Here we propose a fertility clock determined by social norms, preferences and systems which can be called a “sociological fertility clock”. The aim of this study is to illustrate this approach by calculating the family status of women at the end of their reproductive ages conditional on the achieved family status at selected younger ages using multistate life tables. Swedish data from the Generations and Gender Survey is selected as an example to illustrate our methods. At age 35 the risk of infecundity starts increasing, however, our results show that the sociological fertility clock starts rapidly ticking even earlier than this biological fertility clock. The biological fertility clock ticks at a similar speed and age for all women irrespective of their year of birth, contrasting with the great dynamic seen in the sociological clock by cohorts, and which also times the onset of fertility decline.
Presented in Session 127. Fertility Timing