Assuming you're not in love with the other person, women and men cannot be friends; they can have something resembling a friendship, but it's a superficial social thing.
Ladies - you know this is true. All of your male friends want to fuck you, but they have you on a sliding scale, like
"I really want to fuck Nicole so bad it hurts"
"I'd fuck Nicole after a pint"
"I'd only fuck Nicole if I'm mad horny and there was absolutely nothing better on offer"
I can prove it, too. Take your male friend, get him alone in your place, then strip down naked in front of him, lick your own tits and put a hand on his crotch.
Will he say "Sorry, but I don't think we should complicate our friendship", or will he reciprocate?
Yeah, thought so