I am under the impression that male and female brains look the same. ... We're all human, after all, and a statement to a male brain should look alike to the statement to a female brain. All authors ever play characters of both genders, assuming the book isn't co-written by a male and female writer and they let each other do the parts with the male and female characters, and that's just stupid.

I'm going to say what said person told you was stupid. There's no "way to play a female character". It's the same as playing a male character. You know how their personality is, and you amount all their experiences up until that point to factor into the situation at hand. This makes every character unique. Sure, female experiences and male experience usually differ in a specific way, but all-in-all this is just a generalization and not fact. You can't say "you play a character badly", because that could just be how that specific situation that character would react. The only time this isn't necessarily correct is if you're playing a character you didn't create.

Just keep playing as you like. They can't tell you how to play your characters. I play both male and female characters as I please, both as GM and as player, as well as a writer. I've not noticed any particular problems so far, with perhaps the exception that many of my characters share my morals a little too exactly. Nothing about gender. So, I'm going to say there's nothing wrong with how you play females, even without samples.

And that's that. Just wanted my word in there.