OK. I'm of the opinion that when the majority of a girl's friends are males, then something is wrong with the girl. And here is why I think so: it's hard for girls to make new female friends because when a girl wants to have a female friend, they look at their personality and how much compatibility and fun they have. On the other hand, girls (especially good looking ones) are approached by guys ALL the time and so it is easy for a girl to make male friends because they approach her for her looks (and make compromises even if they don't like her personality that much). The problem is that girls actually think that these guys are "only" intending to be friends. Us, guys, know that the dude who she just met and who she thinks is only a friend is waiting for the right time to make a move. A lot of girls don't realize that.
I personally don't have a problem with my gf hanging out with male friends as long as I'm invited (it's up to me to come or not) but as long as I know that she's not hiding him from me.
In fact, there is this guy who asked my gf out but she told him that she had a bf. They agreed to go out as friends. She goes out with him sometimes, and I know what his intentions are, yet I'm OK with. Well, it doesn't make me feel good that a guy is taking my gf out but I know that she told him where he stood. He's actually so scared of meeting me. We never met. What a wuss