S particular settings. In Bangladesh, per capita income is low;<sup>population growth rates, while declining, remain</sup> high; and people sccept high physical risks in order to make a living<sup>in cyclone-prone areas, as the death toll</sup> of over 100,000 from the cyclone of April 1991 dramatically<sup>illustrates. In this setting, it seems probable</sup> that the social costs of children exceed their private costs,<sup>and that high fertility is slowing development</sup> progress. In the African Sahel, where the rules regarding<sup>access to common property rights seem to be</sup> breaking down (at least in part due to rapid population<sup>growth), and weak governments have nc-t succeeded</sup> in imposing new more for.nal institutional and legal<sup>arrangements, continued rapid population growth can</sup> only exacerbate the resulting set of problems.<sup>Wherever populations are highly dependent on natural</sup> resources, opportunities for migration are limited,<sup>and policies favoring capital have reduced the retvhns to</sup> labor, rapid population growth is problematic. in many<sup>countries, as tor example the Philippines, Indonesia</sup> and Nepal, population pressures on natural resources<sup>are producing major environmental deterioration.</sup> 13. Thus the issue of population growth neeAs to<sup>be addressed urgently in some countries, but less so</sup> in others. Prudence suggests tha. Bank staff be<sup>alert to the potential negative effects of rapid population</sup> growth in a set of key countries, and be equipped to<sup>discuss the population issue with policymakers in those</sup> countries. In virtually all of Africa (including North<sup>Africa), much of South and Southeast Asia, the Middle</sup> East, and certain parts of Central and South America<sup>(e.g., El Salvador, Nicaragua, Peru, Bolivia), the high</sup> potential costs of continuing rapid population growth, relative<sup>to the low costs of efforts to reduce that growth</sup> (as discussed below), suggest that Bank staff should<sup>urge upon policymakers a precautionary principle: steps</sup> to reduce fertility appear, from a macroeconomic perspective,<sup>to be advisable. This is especially true if one</sup> considers that, in may countries, what is done today will<sup>strongly influence population size 50 years from</sup> now. A delay of even a decade in starting fertility decline<sup>in some rapidly growing countries could mean</sup> that they will have to deal with a population a third bigger<sup>than they would otherwise have by mid-century.</sup> 14. Moreover, the Bank, in virtually all of its policy statements<sup>on population, has emphasized not just,</sup> or even primarily, the effects of rapid population growth<sup>on economic growth. A major emphasis has been</sup> on the effects of large families on the poor, and particularly<sup>on poor women and children.5</sup> These negative effects are pervasive even in countries, including much<sup>of Latin America, where significantly negative</sup> macroeconomic consequences of population growth are not<sup>obvious.</sup> _15._ The negative effects of high fertility in poor households are in part associated<sup>with unwanted fertility.</sup> Survey data clearly show high rates of unwanted fertility throughout<sup>the developing world. A good example</sup> of evidence that unwanted births reduce parental investments<sup>in children comes from a study of twins in rural</sup> India; for families in which the most recent birth was of twins, implying<sup>some element of unwanted fertility,</sup> the children were significantly less likely to be in school.<sup>But even where fertility is wanted, in the sense</sup> that couples had access to but did not use contraceptives, many<sup>and closely-spaced births are associated, for</sup> example, with higher maternal and infant mortality, with reduced<sup>expenditures per child on schooling, and</sup> so on.6 ' The Bank has also emphasized the potential negative<sup>effect of high fertility on the distribution of</sup> income, where at least the theory linking rapid population<sup>growth to greater income inequzity is</sup> straightforward; unless there is perfect substitutability<sup>among factors in production, increases in the supply</sup> of unskilled labor relative to other factors will reduce<sup>the return to unskilled labor relative to other factors.</sup> G See, for example, Knodel, _et al_ (1990).