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Aotearoa New Zealand's fertility rate continues to fall, according to data released by Statistics New Zealand this week. The country's fertility rate has been below the replacement rate of 2.1 since 2013.
The total fertility rate refers to the average number of births that women in New Zealand would have over their lifetime, given current birth rates. And the replacement rate is the number of births needed, on average, for the population to replace itself in the long term - with no migration.
Last year marked the lowest fertility rate on record: 1.56. The average across OECD countries is 1.59.
"The latest decline reflects a continued trend of smaller average family sizes and increased rates of childlessness, although the total fertility rate is also affected by changes in the age of giving birth," Stats NZ population insights analyst Rebekah Hennessey said.
The data
It can be misleading to use the total fertility rate as a proxy for family size. Instead, annual fluctuations can indicate changes in the timing of births. In 2023, the median age of women giving birth in New Zealand was 31.3. It has hovered around 30 years since 1999, compared with around 25 years in the 1970s.
While the internationally accepted replacement level for developed countries is 2.1 births per woman, the actual replacement level will vary from country to country.
In the early 1920s, the total fertility rate was around three births per woman. It then declined, before rising dramatically from the mid-1940s, peaking at 4.3 in 1961. By 1980, the total fertility rate was sitting around two births per woman.
New Zealand is not an outlier. Falling fertility rates have become the norm in most developed countries, even prompting pro-natal policies in places such as Singapore, China, and South Korea. The latter was reported to have the lowest fertility rate in the world - falling to 0.78 last year.
"There are a number of countries [...] which are beginning to panic around the decline in fertility but given all that has been tried, there is very little that seems to work," said Paul Spoonley, a demographer, distinguished professor emeritus at Massey University, and honorary research associate with the College of Humanities and Social Sciences.
A moment for paternity
A quick side note. Fertility is often - unfairly - talked about as a women's issue. And fertility rates are tied to people who give birth. But there is increasing interest in the "male factor" in the fertility decline.
Paternity data is, for obvious reasons, harder to capture. About 5 percent of birth registrations do not include a father's details.
According to Stats NZ, males aged 30-34 years have the highest paternity rates, the same age group as women for fertility rates. The median age of fathers at the time of the birth of their child is just over two years older than that for mothers.
The decline
Stats NZ said declines in fertility rates in New Zealand and internationally reflected a range of factors, including changes in female participation in education and work, changes in costs of living and raising children, and changes in access to contraception.
Spoonley agreed: "The main two factors are the still rising educational qualifications of females combined with participation in the labour market, followed by the cost of having children, with environmental considerations also in the mix."
A review published last year by academics at University College London found a growing number of people were choosing to be childless due to complex concerns about climate change. Overall, stronger concerns were associated with a desire for a smaller number of children or simply none at all.
What's next?
Most obviously, the age profile of places will change - becoming older. And we will see more "hyper-aged" areas, where people 65+ will make up more than 20 percent of the population.
"I have always said that the fertility rate will continue to decline," Spoonley told RNZ. The expected, post-Covid spike did not appear to have helped. "We will see fewer in our education system [...] and that will present challenges for the numbers available to work."
Education Ministry estimates suggest rolls at primary and secondary schools would fall nearly 30,000 or 4 percent nationally by 2032.
As well as less need for schools, an older population entails a higher need for health and aged cared services, and a need to rethink pensions and immigration policies.
On the other hand, an endlessly growing population is also unsustainable.
Currently, the only way of addressing lower fertility and ageing, associated workforce shortages, and "to some extent population growth", is immigration, Spoonley said.
"New Zealand had a population growth rate of 2.8 percent last year; the average for the OECD is 0.4.
"Immigration impacts are significant."
