Demography, not democracy, will be the most critical factor for security and growth in the 21st century. Booming populations are a drag on developing countries, and low fertility rates are sapping growth in developed societies. The poor are making themselves poorer through rising birth rates, and the rich will have less dynamic societies because they are not replacing themselves fast enough. Population growth is outstripping the capacity of governments to deliver basic services in the Middle East and Africa, producing breeding grounds for extremist and terrorist movements. Rich societies will, in turn, see migration from these places as a threat—and they will resist.

Sex, marriage, and procreation may not be beyond the reach of government influence for much longer. Governments facing population explosions and implosions will soon have no choice but to grapple with matters generally considered private.

Efforts to cajole and educate populations into more positive procreation trends have had only limited success. European states, for example, have made Herculean efforts to reverse declining fertility rates, with disappointing results. Singapore’s fertility rate is a dangerously low 1.25 percent. Pro-natal policies have increased fertility only slightly. Without immigration that often exceeds the natural yearly growth, Singapore’s economic growth rate would be as sluggish as Japan’s.

When public campaigns have partially succeeded, as in some Scandinavian countries and in France, they have forced society to reconceptualize the roles of marriage and the family, with the father taking on more of the mother’s role, a transformation Asian families find difficult to accomplish. Even then, these countries are unlikely to get fertility rates to exceed replacement levels. ...