Two of 5-year-old Sophie's favorite little girl friends (also ages 4-5) were going around chanting, "No boys allowed! No boys allowed! No boys allowed!" Sophie immediately got serious and left the play, something I never see her do. I watched her watch them for awhile, and then she approached them with the serious look still on her face.
She confronted her little friends, told them that she didn't like them saying, "No boys allowed" and emphatically said that boys are just as good as girls and that she didn't want to play a game that would exclude them. They disagreed, but Sophie remained undaunted. Ultimately, the 2 girls went off to play without Sophie and Sophie sought out some boys to play with instead.
I really admire her for that. At age 5 she showed more strength in her convictions than many adults I know.