I never call a male a boy, but sometime I call a female a girl. I think that seems wrong but often the reason is that I don't want to say woman as it sounds formal and kind of oldish. Just like I almost never refer to a male as a man.

I never say, "I talked to this man at work the other day." I would instead say, "I talked to this guy at work." Somehow, it doesn't even seem to matter what age the male was, I almost never say man. (e:hodown) says she says dude for where I say guy.

The problem is that Gal - what I think is the female equivalent of Guy - seems so colloquial and not very popular, not to mention it kind of comes off as having a sexist tone, even when unintended - like broad. Maybe its because of the generation that would typically use it. "I talked to this girl," sounds demeaning. "I talked to this woman," sounds cold and unfriendly to me.

And Then There Is You Guys
What's worse is that I often find myself saying "you guys" when referring to a group of woman. Approach by a group of female friends: "Oh, I haven't seen you guys in so long." You gals sounds sound ridiculous and y'all is way to southern colloquial. I could always use the more Buffalo based expression. "I have seen yous? in so long" I don't even know how to spelled it, it is pronounced like "use."

So what should I say? I think I might just never refer to females with pronouns again to avoid the embarrassment. But then thats kind of weird too. It almost like the language makes it difficult to refer to females

Gosh just try and look up all these terms on google images and it give you an idea about their usage.