The quantitative genetics of allocation to sexual functions was examined in the andromonoecious plant, Solanum carolinense. A restricted maximum likelihood (REML) analysis was employed to determine heritabilities and genetic and environmental correlations for flower number, the proportion of those flowers that were male, and the size of flower parts (corolla diameter, pistil length, and anther length and width) in each of three populations used in a diallel crossing design. All floral characters were highly heritable. The sizes of flower parts were positively genetically correlated with one another, which will restrict the independent evolution of these parts. Negative genetic and environmental correlations exist between flower size and proportion male flowers, indicating the potential for the evolution of individuals with either many, small male flowers or few, large, cosexual flowers. The high heritabilities of the traits examined as well as the genetic correlations among them indicate the potential for the evolution of gender specialization in this species, because flower size and number have the potential to affect sex-specific reproductive success.