Generic noun phrases (e.g. Tigers are fierce) are of interest for their semantic properties: they capture ‘essential’ properties, are timeless, and are context-free. The present study examines use of generic noun phrases by preschool children and their mothers. Mother–child pairs were videotaped while looking through a book of animal pictures. Each page depicted either a single instance of a particular category (e.g. one crab) or multiple instances of a particular category (e.g. many crabs). The results indicated a striking difference in how generics vs. non-generics were distributed, both in the speech of mothers and in the speech of preschool children. Whereas the form of non-generic noun phrases was closely linked to the structure of the page (i.e. singular noun phrases were used more often when a single instance was presented; plural noun phrases were used more often when multiple instances were presented), the form of generic noun phrases was independent of the information depicted (e.g. plural noun phrases were as frequent when only one instance was presented as when multiple instances were presented). We interpret the data as providing evidence that generic noun phrases differ in their semantics and conceptual organization from non-generic noun phrases, both in the input to young children and in children's own speech. Thus, this simple linguistic device may provide input to, and a reflection of, children's early developing notion of ‘kinds’.