A number of “seven billionth” babies are being honored around the world. The Philippines was chosen as the first country to celebrate the symbolic birth – feting a baby girl born late October 30 in Manila.

The UN looks at the 7 billion milestone as a sign of people living longer and of improved birth survival rates.

One of the authors of a report from the UN Population Fund, Richard Kollodge, says many low-income countries of sub-Saharan Africa and some in Asia have seen a growth in population that is outpacing economic growth rates.

Asia's population of 4.2 billion makes it the world's most populous region.

Africa's population is expected to triple to 3.6 billion by the start of the next century.

Fertility rates in many European nations and Japan have dropped below the replacement rate, causing concern that shortages of labor and productivity could threaten the quality of life.