Why do girl matter more then boys?

Hi I'm breanna. I'm 15. I always wonder why do parents care when, where, and what there daughters are doing but they don't care what there sons do. I live with my mom and when I want to go to a friends house or party but she won't let me. But when my brother was 15 my mom let my older brother have sex in his room. WTF? I have a boyfriend and I want to spend time with him and some times it's a no.