They be seeking your support to stand up to others. They may believe that there is something wrong with them. They may be ashamed and afraid of being different. People are sometimes discriminated against because of gender, race, looks, sexual orientation, family and life styles. Bias can lead to lower self-esteem, unequal opportunities, and health and emotional problems.
Unfair bias harms the person, group and society.
Decide on a response that gets your message across and teaches what you want your child to learn. Boys should act one way and girls, another. One should behave the way their gender is supposed to behave. I'm sorry your friends are picking on you. You are our child and I love you whatever you do.