Today begins the one-week countdown to 31st October when the world population is predicted to reach seven billion.
That's a rise of two billion in less than a quarter century.
The big question is how long the planet can continue to satisfy the voracious appetite of its growing number of human inhabitants.
In fact, over the past six decades, the global fertility rate has been cut in half. Statistically from five children per woman to 2.5. But 78 million babies are still being born every year, almost all of them in developing countries.
The UN says women in these countries are having so many babies because of poverty, lack of education, income and access to birth control.
Not only that, they and their children face a high risk of poor health, and early death. So the UN is highlighting the need to boost education and employment opportunities for poor women: in other words, address the poverty, and the demography will look after itself, as it did in Europe.
Barbara Plett, BBC News, New York
Projections: kalkulasi, perkiraan
the Milestone: tonggak bersejarah
to take stock of: memikirkan secara cermat tentang sesuatu untuk mengembangkan kebijakan
trends: perubahan yang terjadi pada suatu waktu tertentu
the voracious appetite of: penggunaan sumber daya secara cepat
fertility rate: jumlah rata-rata bayi yang lahir dari setiap wanita
access to: ketersediaan
to boost: untuk meningkatkan atau memperbaiki
address: mencari solusi masalah
the demography: komposisi penduduk