conflicting evidence age at which children seek out gender-appropriate behaviour. Kohlberg's and Martin and Halverson's theories agree that children play an active role in their own gender development, searching the environment for what counts as stereotypically gender-appropriate behaviour. However, they disagree on when this starts to happen. Kohlberg argues that children must achieve gender constancy before they begin to demonstrate gender-appropriate behaviour . Once they have, they look for gender-appropriate role models to imitate.