'It's a boy because he's painting a picture': age differences in children's conventional and unconventional gender schemas.

Two studies investigated the development of children's gender knowledge using a procedure designed to tap into children's unconventional gender beliefs. Study 1 revealed a developmental progression with 34 3- to 4-year-old children providing more unconventional reasons than conventional reasons to explain the gender of a series of drawings. By contrast, 39 5- to 6-year-old and 42 7- to 8-year-old children provided more conventional than unconventional reasons.