Hi, in part this is asking about how you respond at times of discrimination and why.
An understanding of just how damaging prejudice
can be will help you know why it's good to want things to change. This will enable people and organisations to refuse showing prejudice or discrimination against, or towards each other, rather they will want to work together knowing this will improve the outcomes for children's, and later adult's success, their well-being, ability to work posistively with others, work through problems/disagreements/conflicts without aggression and be happy with their choices and their life.
Adults can discriminate against others and show their prejudice in ways that hurt, harm. Children show how they've witnessed/seen and been influenced by this prejudice and demonstrate that learning, feeling it's ok, acceptable, normal for them show the same discrimination against others.
Intervene - firmly, knowing why you feel discrimination has occured.
Ask what children mean by their comments, so you can examine the prejudice and discuss for example: why they feel boys can't play with dolls, girls can't play with action figure capes.
Don't become aggressive - professional practice shows respect for all view points.
Ask for help whenever you feel uncomfortable about something. Challenging discrimination indirectly is a way that will help your confidence in dealing directly with it on another occasion.