"Richard Ham: From the outset, we wanted to create a character customization system that was so deep and varied that you would never run into another player that looked exactly like you. As we got deeper into development, we were faced with an incredibly tough choice: massively cut back the amount of customization options as well as the quality of the assets, or cut female models.
Ultimately, we didn’t want to compromise our initial vision of having incredibly varied character customization without hurting the artistic quality, so we decided to only focus on male customization and make that the best we possibly can. This was a very, very hard decision for us to make, but we feel that it was the right one for the overall quality of the game. (http://brink.chefenco.com/cut-brink-female-characters-a-very-very-hard-decision-to-make/)"
"Paul “MoP” Greveson Profile – Technical Artist: I’d love to see female characters in Brink too – I think we all would! In fact, we did explore female characters in our early concept art. However, given the realities of development, we had a choice between having a wide range of options for male characters, or a much more limited set of clothing options that allow for both genders.We figured it would be the best use of our time to have a big set of quality customisation options for males instead of less and lower quality for females and males."
"Aubrey “Bezzy” Hesselgren – Technical Game Designer: Also, you’d practically double up on animation (women move noticeably differently to men) doubling up on the production of animations, and the memory footprint for that. When asked wheter it would be worth to reconsider female characters instead of extra map Bezzy explained. Unfortunately, it doesn’t work that way.The people responsible for levels and gameplay are not the people responsible for the character customization assets. Not having female characters doesn’t get us extra time for other things. If only!"
And, as a bonus, one more reason female characters would be difficult.
"MoP again: One of the only things we really found challenging about fitting female characters into Brink’s gameplay proper is that in order for gameplay to be balanced, the females would have to be roughly the same height and width as the male characters in order to prevent any issues with hit detection or visibility. Since women naturally tend to be smaller than men in reality, it meant we had to be pretty exaggerated in terms of their proportions when concepting the early designs. It actually worked fairly well in the end but it was a lot more work than getting the males to look right at the same size. So, even though we did those early concepts and model tests, we had to end up dropping it for all the reasons that myself and other SD crew have mentioned so far."
http://brink.chefenco.com/splash-damage-explains-the-lack-of-female-characters/