I've heard of three female SE4 players. I've known many female RPG players, too, most of them quite good players who enjoyed the games without gender-related issues, although a I have seen several er, unappealing male RPG players, who were not in games the female players played in.
As for SE4, my wife has thought SE4 looked interesting, but seemed way too complex for her to want to get into. I've heard that comment from several male players, too.
Also though, one thing that turns me off about SE4 that I expect would tend to turn off most female players, is the general assumption of antagonism, megalomania, and above all, the default to violence and genocide. Even when you try hard not to, it's all too easy to accidentally murder billions of peaceful unarmed civillians, who may even be of your own race if an enemy captured one of your planets. IMO, that really sucks, unless you assume everyone is a genocidal maniac. Then there's the "all ships fight to the death whenever they meet anyone without a treaty" thing.
PvK