After a baby bump following Peter Costello’s famous call to arms for Australians to “have one for mum, one for dad and one for the country”, the fertility rate has ebbed by nine per cent since 2011. Sydney’s fertility rate is now the lowest of any capital city in the country, tumbling by 15 per cent over the past six years. It is well short of the natural replacement level, meaning Sydney’s overall population would fall without migrants. Melbourne’s fertility rate is the second-lowest of the nation’s capitals, having fallen by four per cent over the past six years. Like Sydney, without migrants, Melbourne’s overall population would be falling. Melbourne's CBD is home to more than 45,000 people but in 2017 just 238 babies were born to local residents, giving it a fertility rate of 0.58 per cent. Across the Yarra at Southbank there were 190 children born to its 22,184 residents.

The city’s baby desert runs down South Yarra, through Prahran to St Kilda. Melbourne’s outer suburbs are where the cribs and nappies can be found. Broadmeadows (2.58), Campbellfield-Coolaroo (2.52) and Wollert (2.69) are the most fecund part of Melbourne. Lisa and Daniel Remeeus with children Inara and Talon Credit:Chris Hopkins Daniel Remeeus has seen both sides of the baby divide.

The Age spoke with the construction manager outside a shopping centre in Broadmeadows with his wife Lisa, son Talon, 5, and daughter Inara, 3. Today the Remeeuses live in the neighbouring suburb of Hadfield. But as a single man, Daniel lived in St Kilda. "I went out every weekend, spent a lot of time in pubs, cafes and bars," he said. "You had that freedom to walk out the front door and head to the foreshore for a walk whenever you felt like it, on hot summer nights. “Obviously now it’s more of a family life, more home-based, fewer nights out.”

The family moved to the northern suburbs to be closer to the government agency in which Lisa works as a planner and also to her parents, who help look after the kids. Lisa’s parents moved to Australia from Lebanon as a young couple and have stayed within the triangle of Broadmeadows, Hadfield and Glenroy ever since. She said traditional Lebanese families were often large and that practice had carried on in Australia. Lisa recalled seeing that cycle continue as a high school student in Glenroy. “By the end of Grade 12, four girls were pregnant, they’d been back to Lebanon and married off,” she said.

But the mother of two, who was recently promoted, said those large families may soon become a thing of the past. “Times are changing now, women are having a more liberal lifestyle, they’re having more of a professional life outside of their family,” she said. The tiny community of Robinvale on the Murray River in the state's north-west has Victoria's highest fertility rate at more than three. Despite Robinvale's population dropping to 3359 last year there were 71 newborns in local homes. Australia’s often divisive population debate, thrust back into the spotlight again this week at the Council of Australian Governments meeting, mainly focuses on the headline permanent migration figure and the failure of infrastructure to keep up.

But the reality is without the babies of migrants who now call Australia home, the population would soon be shrinking. The comparison with New Zealand is striking. The Kiwi fertility rate is 2.14 - enough to replace New Zealanders already in the country - compared to the Aussie rate that is 0.24 babies short of replacing every mother and father. “What sort of society can’t create the circumstances to reproduce itself?” asks veteran demographer Bob Birrell. “That is an affront. It implies that young people no longer have the confidence that their society is providing a setting for them to have enough children to reproduce existing population.” Roxburgh Park family Fiko and Seral Karabudakli with children Huseyin and Alpay. Fiko puts local population increases down to “because people here, they don’t work and they have no TV at home". Credit:Chris Hopkins

Cultural change has played a role, but Birrell believes the shift is fundamentally economic. “The younger age group 25-34 is dropping like a stone,” he says. “There will be some compensation as they reach their late 30s which perhaps reverses some of the trend, but births delayed ultimately add up to births cancelled.” Australian Population Research Institute data show that the proportion of young couples aged 30-34 who are renting in Sydney and Melbourne has gone up five percentage points since 2010 on the back of soaring house prices that have only just started to cool. “It’s very difficult for couple who want to raise children to find a family friendly dwelling which would allow them to get on with the business of raising a family,” Birrell says. “There is a very clear correlation and causation.”

Nationally, the number of children born across the country fell in 2017, down by 1962 on the 311,104 who arrived in 2016. While NSW bucked the trend it wasn’t enough to offset some large falls in other parts of Australia including a 931 drop in Western Australia. The falls are set to exacerbate what is already looming a major labour market problem. A recent a study by Shah and Dixon shows there will be 4.1 million new job openings in Australia between 2017 and 2024. Robert Abboushi with children Zyana and Mason. "I can't speak for everyone. I just like kids," he says. Credit:Chris Hopkins Over two million of these new openings will be due to “replacement demand”, effectively replacing the retirements from the labour force of baby boomers.