Well, I will play a game as either really, but given the option I'd prefer to play as a female. I love my female characters but that doesn't stop me from playing games that only feature a male character. Unfortunately, we must take what we can get when we can get it sometimes, but for a company like Bioware that has had such a long standing history of allowing players the option, I would be extremely upset if they suddenly did make a game that forced me into either role.
Giving people the option can really only help an RPG. For an action/adventure game, it may not help as much (I can't imagine playing BG&E without Jade for instance) as long as the main character is not being formed by player choices. When a game follows a preset path without player choices, the game is more like an interactive movie, whereas most RPGs that allow choices are more founded on the growth of the main character, and thus allowing varying genders enhances it. So, they each have their place.
And anyways, have these same ladies you speak of never played the Zelda series just because you can't play as the Princess?

Oh, and as for what draws me to a title...usually quality and a good story. I'm not interested in wasting my time on trash. Of course, there isn't a clear characteristic about a game that makes it irresistable to me.