The 'Alien' and 'Terminator' films (original ones, at least) have a lot more female fans than is supposed, precisely because of how iconic Ripley and Sarah Connor are in culture as heroines.
Way early on, I thought Gearbox might opt for the main character of this title being either a female Marine or having the option to switch between genders, because of that very reason. Seemed like an obvious marketing angle to me.