[영문]The economic contribution of children to their parents' households has long interested demographers because of its potential to influence fertility levels. Valuing children's labour in pre-industrial economies, however, is inherently difficult. The same is true of women's labour, a crucial component of any analysis of net production. Here we use Mead Cain's seminal study (Population and Development Review 3(3): 201-227, 1977) of children's economic contributions in a Bangladeshi village to illustrate these points. We combine Cain's data on landless women's and men's hours of work with data on the efficiency per hour of work from other pre-industrial settings (Mueller, Population and Development: The Search for Selective Interventions. Baltimore, MD: Johns Hopkins University Press, pp. 98-153, 1976; Kramer, Dissertation, Department of Anthropology, University of New Mexico, 1998). When women's labour is incorporated, we find that the Bangladeshi children begin to produce as much as they consume by ages 10 (girls) or 11 (boys). Despite these productive contributions, neither women nor men 'pay' for their cumulative consumption until their early 20s. We believe our methods could be usefully applied in other contexts.