That's not particularly unusual; it's easier to break the ice when there's no question of ulterior motive or interest.

I feel off-kilter speaking with strangers that I find attractive in a professional setting; I have to keep telling my brain to ignore itself and act normally. This isn't unique to any gender -- the other day I was ordering lunch in the neighborhood, and the person behind the counter was mooning at me to a degree that actually made the interaction uncomfortable.

I don't take it personally; that's how people are, myself included. I know it can be slightly uncomfortable, but as long as we're trying to be professional with and understanding of each other, things generally work out.