Gender favoritism

Why do people have so much gender favoritism? Usually in preference of boys. Time after time my nephew has been favorited over my girls including today when someone actually had the balls to say my nephews birthday party was more important than my daughters birthday party all because he was boy. They said this to everyone at the party This kind of thing has been said over and over again. Why? Each gender is a blessing and to be loved equally. How do you even react to this? I literally went off and cried and then got angry. Just because they are girls doesn’t mean they’re second rate to anyone. 😡