Male children (8-9 years) are reported to have a higher sensitivity than male adults to the sweet tastant sucrose when small regions of the anterior tongue are stimulated. The present study investigated the hypothesis that the higher sensitivity was due to a greater density of fungiform papillae and taste pores (buds), since it has been reported in adults that increased densities of these two structures correlates with increased taste suprathreshold sensitivity [Physiol. Behav. 47 (1990) 1213]. Quantitative measures of the number and size of papillae and pores in two areas of the tongue that had been shown to have a higher sensitivity for sucrose were achieved in 20 male children 8-9 years of age and 20 adults 18-30 years of age, using videomicroscopy and NIH Image software. Customized templates and a red food dye were used to define the equivalent tongue locations across the 40 subjects and taste pores were stained with methylene blue. Children were found to have substantially smaller papillae than adults but significantly higher papilla densities in both areas. Similar numbers of taste pores per papilla were found for both groups, resulting in children having much higher taste pore densities in each area than adults. Other differences included smaller taste pore diameters in children compared to adults, and the papillae tended to be rounder in children. Overall, the results support the hypothesis that the higher densities of fungiform papillae and taste pores in children underlie their greater sensitivity for sucrose in the two areas. In addition, the anatomical differences between adults and children indicate the sense of taste is in a state of development during mid-childhood.