While my longest-running roleplaying character on a MUD was male, he was also nonhuman. With that noteable exception, the overwhelming majority of my characters are female, like myself. I suppose that I could play a male character but it never seemed necessary to the concept, or comfortable. Actually, one of my more successful character concept was a deliberate inversion of the expected. She was a female gnoll, and extrapolating on the idea that gnolls are from a matriarchal society (hyenas are), she was a rowdy boisterous brawler, fond of alcohol, aggressively flirting with an occasional side of objectifying men, and the notion that starting a friendly fight was a good way to get to know somebody. She was tons of fun. That's probably the closest I ever got to playing a stereotypical 'male' character.
In general though, I think I'm still working on my roleplaying technique, rather than having everyone react like a recolour of me, but with a more idiosyncratic way of speaking. Playing more animalistic, anthropomorphic, or otherwise further-from-human races is a way to get some extra roleplaying mileage as I speculate about the psychological differences and get to roleplay/emote the quirks of physiology.
So I've never felt comfortable with the idea of roleplaying male characters the same way I'd never felt comfortable writing fanfiction: sure I was going to get some small details wrong that would throw the whole thing off. I might take Astral's advice in the future if I was ever inclined to change that though; a swashbuckler-and-fedora version of my younger brother would be fun, and I'm pretty sure I could at least give that good shot.
I'll second Astral's observation that it's not only men who start in with the "My large breasts equal mind control!" power-fantasy. The one time one of the DMs at my old university tried to whip up a quick fantasy GURPS game, his girlfriend (who didn't usually play) wanted to solve every problem with beauty, mind control, and sex appeal. He wasn't egging her on or trying to reward this tactic (though it was ruled to work a few times), but it was...disruptive. Although that wasn't the only factor, we dropped the game after one session.