"Honestly, adding female soldiers to character customization wasn't about trying to lure more people into the game. It was actually just about acknowledging the people who already play our game," Rubin says.
Enngine limitations were another contributing factor in the franchise's lack of playable female soldiers.
"It wasn't until we rewrote the way character memory is handled - that we could do 'Create-a-Soldier,' that we could do customized characters - that the possibility of having female soldiers really came to fruition," Rubin explains.
"Bringing female characters into Call of Duty: Ghosts wasn't something that was limited generation, it was limited by the engine itself."
Call of Duty: Ghosts (8/14/13)
When the new engine for Call of Duty: Ghosts was built and customization became possible, the ability to select a gender "was an obvious choice," Rubin says.
"There's a huge portion of our fans that are female gamers," Rubin adds. "It was less about getting more people and more about appreciating the people we already have."