Research support for gender constancy comes from Damon who told a story about George a boy who liked to play with dolls, to children.
The children aged 4 said it was fine for George to play with dolls but the children aged 6 thought it was wrong .
This is because they had gone beyond understanding what boys and girls do to developing rules about what they should do (gender stereotyping).
This suggests that children who have achieved constancy form rigid stereotypes regarding gender appropriate behaviour which increases the validity of Kohlberg's theory.