I'm a male, but I do believe that women are just as good as (if not better than) men in most aspects of everything. If this were like most other cases, I would be very against the exclusion of female options. However, trying to look at this from an objective point-of-view, I can't really get too mad about it.
I think the people who are up in arms over this are expecting too much from the developers.
Granted, I don't know as much about this game as I probably should to be able to argue one way or the other, but... from what I've seen, what's being touted is the "revolutionary" movement system and extensive customization options.
Now let's compare this game to somewhat similar products on the market:
Team Fortress 2: created by Valve, a company who is recognized for creating "strong" female characters in their games. Alyx Vance and Chell (though I wouldn't exactly say the latter is well-developed) are just two examples of interesting and nonstereotyped female characters they've created.
But still, for their immensely successful multiplayer sequel Team Fortress 2, they decided to go with an all-male cast (though Pyro's status is questionable?). I think the reason for this could be, like for most things Valve does: IT WORKS BETTER. The classes are charismatic and easy to recognize on the field precisely because there is just one gender for each. And that gender happens to be male because, well, I dunno. Audience? Silhouette recognition? Easier to render?
Enough about that game. I've hardly played it, anyways. Keep in mind that Valve's other popular shooter, Left 4 Dead, does feature female characters. Zoey in the first, Rochelle in the sequel. Are they included in the quartets for the sole purpose of not offending those who would be angry if they were absent? Possibly, but they are at least as well-developed as the other Survivors, so no use complaining there.
How about Monday Night Combat?: Feminists may argue that the Pit Girl characters in MNC are demeaning, sexualized idols, but there is one playable class, the Assassin, who is female-only (as the other classes are male-only). Whether this was again a decision made so Uber would be able to say "look, we aren't sexist!", or because it worked better from a visual or technical standpoint, I can't say. But they had a female in there, so whatever, right?
I feel like I'm babbling too much about things that hardly pertain to the topic, but I'm getting back to my main point, so bear with me:
Both Valve and Uber have, some time after release, implemented customization options to their respective games. TF2 has hats up the wazoo, and MNC has a few hats and outfits as well.
But the customization options of both games pale in comparison to the arguably unprecedented (in an FPS, at least, I think) amount of options available in Brink.
Also, while I'm not ragging on the quality of the animation or characterization in either aforementioned game, neither could claim to offer as much unique manipulation of the human male skeleton as Brink does.
So basically, Brink is already doing more than a lot of the competition. Why are there people getting angry at Brink, but not the above games?
IN CONCRUSIONS: If Brink ends up being great in the gameplay department, then the ancillary details should be weighed less heavily. And those details seem to be great anyways, even without vaginas. The game could've offered jack poop as far as customization goes, and if the gameplay was good, everyone would(should) be satisfied. But the developers went beyond the call of duty (no pun intended), offering a new movement system that is rather unlike anything done before in a game like this. So even though they've done all that, there seem to be quite a few people who are saying "That's not enough! nO tits, no PURSHAASE!"
Those people should lighten up, and not expect this one humble game to end thousands of years of inequality. Appreciate what the developers are already doing, and don't expect them to champion your cause when they've already got their hands full with what they're trying to accomplish. Labeling them sexist bastards and refusing to purchase what may (or may not) be a great game is your prerogative, but condemning them for trying to innovate (just not quite as much as you'd have liked) seems foolish at best.
Oh my gosh, that post got needlessly long and repetitive.