Research indicates that young children, unlike adults, have a generalized tendency to view not only artifacts but also living and nonliving natural phenomena as existing for a purpose. To further understand this tendency's origin, the authors explored parents' propensity to invoke teleological explanation during explanatory conversations with their children. Over 2 weeks, Mexican-descent mothers were interviewed about question-answer exchanges with their preschool children. Analyses revealed that children asked more about biological and social phenomena than about artifacts or nonliving natural phenomena, with most questions ambiguous as to whether they were requests for causal or teleological explanations. In responding to these ambiguous questions, parents generally invoked causal rather than teleological explanations. The tendency to favor causal explanation was confirmed by analyses of transcripts from a longitudinal study of spontaneous speech in a father-son dyad. These results suggest that children's bias toward teleological explanation does not straightforwardly derive from parent explanation.