This article explores trends in the presence and centrality of males and females in American children's picture books in the twentieth century. Using the Children's Catalog as a population base and a time series analysis, we found that the imbalance in depicting males and females varies through the century in a curvilinear fashion. The earlier and later periods of the century show more egalitarian representations of females in titles and central roles. However, when stories involving only adults or animal characters (...) are considered, males become more prominent over time. Changes in literary themes and the position of women during this time span may be useful in developing a theory to account for these trends. (shrink)