The authors explore the hypothesis that--because of the important role children play in collection activities (firewood, water, grazing)--the demand forchildren may increase as local environmental resources are depleted, setting up a vicious circle between resource depletion and population growth. Using a large-scale household data set from Pakistan, with detailed information on fertility and the allocation of time to collection activities, they find that: (i) collection activities absorb a substantial part of household resources--firewood collection accounts for 6.2 percent of household expenditures, valued in collection time; (ii) collection absorbs a quarter of the time of children; (iii) women benefit when there are older children in the household; they work 2.6 hours a week less in household activities for each child aged 10 to 15, and 3.2 hours less for each child over 15; and (iv) there seems to be an inverse relationship between fertility and the availability of firewood; even after controlling for other determinants of fertility in reduced form regressions, the authors show that households that live some distance from firewood have more children, whereas households that live where firewood is more expensive have fewer children.