Second demographic transition
The second demographic transition (SDT) is a postulated and empirically observed decline in fertility to sub-replacement fertility as observed in developed countries, mainly European countries and Japan.
Observed features from a purely demographic perspective
- Substantial decline in period fertility, partly resulting from postponement of births, so that (estimated) cohort fertility of currently
reproducing women is expected to reach a maximum value well below replacement.
- Substantial decline in the total first marriage rate associated with an increase in mean age at first marriage
- Strong increase in divorce (where allowed) and in the dissolution of unions
- Strong increase in cohabitation, even in countries where this was not a traditional practice
- Strong increase in the proportion of extra-marital births
- Catalytic shift in contraceptive behaviour with modern means replacing traditional methods.
Observed sequence of events
- Decline in total fertility rate due to a reduction in fertility at higher ages, decline in crude birth rate at higher birth orders
- Avoidance of premarital pregnancies and "forced" marriages (such as shotgun marriages)
- Notwithstanding that, the mean age at first marriage continues to decline for a while (???)
- Postponement of childbearing within marriage, fertility of young women declines, lower order birth rates decline, this accentuates decline in period TFR
- Increase in judicial separation and divorce (when allowed)
- Postponement of marriage largely replaced by pre-marital cohabitation, increase in age at first marriage
- Cohabitation becomes more popular, marriage postponed until bride is pregnant, increase in pre-marital births, increase in mean age at first birth
- Legislation permitting sterilization and abortion further reduces unwanted fertility: fertility at border ages of childbearing declines further
- Cohabitation gains further support, and is frequently also preferred by the widowed and the divorced
- Cohabitation increasingly seen as an alternative to marriage, extra-marital fertility increases
- TFR's tend to stabilize at low levels
- TFR's increase slightly where women who postponed births start their fertility careers; increase of lower order birth rates at higher ages of childbearing
- Not all postponed births can be born in years of childbearing remaining
- Voluntary childlessness becomes increasingly significant
- Completed cohort fertility appears to stabilize at sub-replacement fertility levels.