Well, not even 20% of the players who were logged onto their EA accounts in Mass Effect 2.Losanme said:Not even 20% of Mass Effect players even played female Shepherd by the way and cutting that feature would have likely been largely inconsequential to the series sales numbers.
It's also worth noting that 50% of that same player pool never finished the game. Granted, that has no bearing on the sales of ME2, but players who actually finish a game are more likely to pick up the next one. Now this is speculation on my part, but I would wager that an overwhelming majority of these likely disloyal customers exclusively played as the male Shepard, and also didn't pick up the DLC or the sequel.
And, at the end of the day, 20% is still a pretty huge part of the player base. No player base is homogeneous, but rather made up of a multitude of minorities. Cut a feature set that appeals to one, and then another, and eventually you'll basically have no customers left.