I work with art for games for about 4 years and I have been in multiple brainstorm reunions to decide art style, which demographics target to, how to appeal to such demographics... and quite honestly, those kind of decisions are taken mostly from pure guess. We had statistics of gender and age, but those don't answer exactly what those populations want from their games.
Once, I was working in a game intended for females from 25-35 age range and there wasn't any females working in the company, because.. well, it's a small games company, so the chances of having a female worker were low. So, what a bunch of IT guys could predict of female tastes? Dolphins. Flowers. Cute animals. Those were the themes that came out of the reunion.
At home, my sister, who was in that age range, was playing Red Dead Redemption. She barely knew how to handle a dual stick controller, but she learned just to play Red Dead, a game about ugly man killing each other. She clocked more than 30 hours in that game and finished it. I said that at work, but the answer were "nah, your sister is a exception". Anyone had any data about it? No... just "gut feeling".
Sometimes, when creating female characters, my boss would come and give his opinion: "You know, why don't you make some big tits? Like those you'd stick your face between them and lick, ya'know?

" He really mean it, he would justify with things like "the kids like it, hell, I like it!". Maybe someone from the team would aproach and say "wow, what a hottie. Man, why don't you make a bigger ass?".
My producer wasn't this type of guy, but he would often accept those kind of ideias because he thought that could boost sales. But honestly, no one knew for sure. It's just like those preconceived ideias that float around... "boys like to jerk off, right?" and then someone would bring an example of a sucessful game that had gigantic tits, like that was the defyning point of its sucess.
It's pretty much impossible to guess what large demographics really want, it's always a guess... and that guess comes from the imagination of the developers, which still is very predominant male. Sexism is in every media, but I guess cinema, music and literature have a more balanced gender ratio producing content, assuring a wider range of representation and consequently, a wider audience. Games seems stuck in this "boys club" corner and are very reluctant of growing out of it.