tar Fund have failed.rnA principal reason that some areas remain mired in povert’ isrnthat populations are far larger than they were when internationalrnaid began. (Populations are still growing, although the rate ofrngrowth has deelined.) Plots of land per farm family are significantlyrnsmaller than 50 years ago, so rural populations are oftenrnimpoverished even in cormtries such as Thailand, where somernsectors have industrialized and modernized. Ethiopia, whichrnreceived massive aid in the early 1980’s to alleviate mass starvation,rnis again in the throes of drought-induced famine—onlyrnnow family plots are half their former size and population growsrnby three percent annually. (With a three percent rate of growth,rna population doubles in 22 years.)rnThird World populations get rapidly larger because fertilityratesrnare higher and mortality rates are lower than when internationalrnaid began. No one would wish to withhold life-savingrnmedical care, but the tragedy is that Western aid also artificiallyrnraised fertility rates (the total number of children born per woman).rnWliy did this happen?rnAwidely accepted generalization is that families in all societiesrnhave approximately the number of children that theyrnwant. I have pioneered the “fertility opportunity model,” whichrnfurtiier stipulates that the desire for children is innate: Couplesrnseize upon seemingly good opportunities to have more children.rnYet ftimily-size targets are tempered by judgments aboutrnhow many children can be raised well given cultural and individualrnexpectations, aspirations that entail alternate uses of resourcesrnand subjective perceptions about resource availabilit)’.rnParents generally behave as if they wanted to provide tiieirrnoffspring with the best possible start in life. Over the long run,rna strategy of restraint combined with good timing appears tornmaximize reproductive success in human societies—and, indeed,rnin many animal species.rnPeople rarely measure prosperity or “plenty” by what is availablernto them but by what they once had, what they want, whatrna relevant comparison group has, and what the future is expectedrnto bring. Humanity’s sense of scarcit}’ can be overcome onlyrnfor fleeting moments, until a new, higher standard of livingrncomes to be taken for granted. After people become used to arnparticular level of affluence, fewer resources or even a slowerrnpace of acquiring wealth may be perceived as privation.rnThe shortfall between wanting and having creates a perceptionrnof scarcity. Thus, the subjective experience of scarcity occursrnwithin a wide range of economic circumstances. At the extremernof poverty, among large families in regions where perrncapita income or access to land is insufficient to provide life’srnbare necessities, the sense of scarcity and the stark reality probablyrncoincide. But in societies that would be considered affluentrnby most objective criteria, a ten-percent decline in income is alsornlikely to be perceived as scarcity. Wlien real wages decline tornthe point that current income does not cover accustomed expendihires,rnthis creates effective scarcity, even at high levels ofrnincome.rnThe subjectivity of scarcity explains the relatively modest familyrnsize that we find across cultures and periods of history, becausernonly rarely have very large families seemed affordable.rnForeign aid, which so often appears as either a windfall or a rescue,rnmade many people lose sight of essential scarcity. (See myrn1993 book. Population Politics, reissued in 2000 with a new introduction.)rnContinuing infusions of foreign aid combined with thernheady experience of throwing off colonial governments (India,rnPakistan, Indonesia, much of North Africa, sub-SaharanrnAfrica), expropriating corporations (Saudi Arabia and other oilrncountries, South America), and populist revolutions (China,rnBangladesh, Cuba) resulted in vast redistribution of, and increasesrnin, wealth.rnIn the short term, aid provided for better health care, free andrnnearly universal education for children, more and better foodrncrops, new and novel infrastructure (including electricity), andrnthe promise of much more to come. Unfortunately, ordinar)’rnpeople began to believe that their future prosperit)’ and well-beingrnwere assured.rnIn such optimistic climates, people marr)’ young, want largernfamilies, and experience closely spaced births. The traditional,rnworldwide disciplines by which large family size has alwaysrnbeen avoided—late marriage and long periods of sexual abstinencernbetween births—were cast away.rnAt the same time, mortality rates, particularly for infants andrnchildren, declined dramatically after World War II because ofrnimproved health care. Theories drawn from (flawed) observationrnof the demographic transition in Western countries suggestedrntiiat families would spontaneously reduce childbearingrnwhen they saw more of their children surviving.rnIn a succession of European countries, infant mortalih’ declinedrnafter or, at best, simultaneously with a drop in the fertilityrnrate. This means that the decline in infant mortality could notrnhave caused the decline in fertilit)’. Demographers were wrongrnin their optimistic assumptions about cause and effect. Itrnshould not have been such a shock to international plannersrnwhen fertilit)’ shot up in most Asian, South American, andrnAfrican countries even while more children survived, the standardrnof living improved, and expectations of rising opportunity’rntook hold in the national consciousness.rnThe connection between perceived economic opportunity’rnand fertilit}’ rates is not pecidiar to the Third World: Motivationsrnand hesitations around the issues of childbearing are wellnighrnuniversal. In the United States, from the colonial era onward,rnperiods of exuberance and economic optimism arernmarked by high and rising fertilit}’ rates. On the other hand, fertilityrnis lower when the economy and tiie average person’s expectationsrnare depressed. Contrast the verv’ low fertilit}’ duringrnthe L’)epression era with the Baby Boom during the 1947-1962rnperiod of postwar prosperit}’.rnThe OPEC cartel and rising oil prices in 1973-74, probablyrnrelated to the onset of inflation and stagnant real wages, causedrnthe U.S. fertilit}’ rate to decline again. Today, one would expectrnthat the strong economy would result in significanfly higher fertilityrnrates. Indeed, fliere has been recovery from the below-replacementrnrate levels of the 1970’s.rnWliat is interesting, however, is that tire Hispanic fertility raternin the United States is significantly higher than the black rate,rnand fully one child per woman higher than the non-Hispanicrnwhite rate. Moreover, an analysis by economist Diane Macunovichrnsuggests that native-born Americans as a group arernhaving fewer babies because of immigration’s depressing effectrnon wages and the conditions of work. Macunovich writes in thernNovember 1999 issue oi Population and Environment that approximatelyrnone American birth is foregone for each immigrantrnwho comes to the United States.rnLeaving Western examples, India is a country where perceivedrneconomic opportunity appears, repeatedly, to havernchanged population size and growth rates, hidia’s populationrnJUNE 2000/1 7rnrnrn