About 10 o'clock last night Australia's population hit 23 million. If the landmark arrival was a newborn, the birth was most likely to have been somewhere in western Sydney.
But given the nation's high rate of migration, he or she was more likely to have been a Kiwi flying in from across the Tasman, a Briton landing in Perth, or even an Aussie coming home after the great OE.
"The 23 millionth person could be a newborn baby, but could equally be a person coming to work in Australia or a returning backpacker who has been away for more than a year," said Australian Bureau of Statistics director of demography Bjorn Jarvis.
Wherever and however she or he appeared, the bureau's population estimate has again fired up debate over how many people the world's driest inhabited continent can accommodate.
It is also bleeding into political fencing over migration levels and the issue of temporary work visas for skilled workers, mainly for the nation's big mines.
The basic maths of Australia's population are startling.
The present growth rate of 1.7 per cent is well above the global figure of 1.1 per cent, is higher even that India's, and streets above the rest of the developed world.
This is adding more than 1000 people a day, a pool of new arrivals that every 19 months equates to another Gold Coast.
Over the past decade the population has risen by about 1 million every three years.
The nation's birthrate has been accelerating, now topping 300,000 babies a year. Much of this has come from couples producing larger families.
But the real driver has been migration, with about 180,000 migrants arriving every year.
The bureau said that in the year to last September net migration accounted for 60 per cent of the nation's population growth.
"This is the highest annual increase in net overseas migration in almost five years," Jarvis said.
The bureau said that if present migration and birth rates did not change, Australia's population would reach 35 million in 2056, and 44 million in 2101.
Other demographers believe the marks will be reached much sooner.
Business has generally welcomed an accelerating population, arguing that more people will fuel economic growth.
But opponents believe a booming population will stretch the nation's resources and environment to breaking point, and that eventually the economy and living standards will be hit.
The public policy think tank the Grattan Institute warned this week that the nation is facing deep, long-term cuts to areas such as health and education, and said the pain would leave no one untouched.
The nation is already struggling to cope with overcrowded hospitals, housing shortages, overtaxed water supplies and shortfalls in other key infrastructure.