With Fallout 1, I originally started out the very first time designing a male character, and while picking his stats (focusing on high Int, Cha, and Agi at the sake of Str and End,) - as my concept of this character formed around these basic ideas, it just... "felt" like my stats were better describing a female protagonist. (And not to be sixist or make broad generalizations - obviously I could have made a character of any gender with any variety of stats and it would have "fit." It was just, somehow, this female character concept sprung up - and it was more appealing and 3-dimensional a vision than I'd had for my male character.) :shrug:
So anyway, skip forward a decade or so and I have Fallout 3. I originally intended to make a male character - but once again, the further I got into character creation, the more it just "felt" like a female would fit the role I had envisioned in a more compelling way. And the one (rather large) hurdle I ran into was the face creation part. No matter how I tried, I just couldn't get a male face that looked quite right - or that I could be satisfied with. It was much easier (somehow) for me to create a female face using the creation tools, that was rather close to what I'd seen in my head.
So, for New Vegas - I figure it's just fate, at this point. I probably won't even try to make a male character. Somehow, all my Fallout characters end up being female. I think, considering the background I know for the game so far, I'm going to go in a slightly different direction - but even my basic stats haven't changed all that much from the first Fallout game.