While the world population continues to demonstrate explosive growth as a whole, the current state of population in developing regions, the so-called "South," is in sharp contrast with that of industrialized regions, the so-called "North." The South has a disproportionately high proportion of child population, as well as high overall population growth rates. Most governments in these areas have sought fertility decline to around the replacement level through family planning programs. The North is characterized by continuous population aging and will face population decline. In order to cope with stagnant low fertility, some governments have sought to raise fertility to around the replacement level by strengthening family policies. In this paper, Professor Makoto Atoh, Director General at the National Institute of Population and Social Security Research, Tokyo, contrasts the populations of the North and South and recommends possible policy options for the governments of developed countries, especially Japan.