I always tend to think in rpgs what gender seems to fit the kind of a playthrough I’m going for. For some reason if I do something like wood elf ranger it would def be a female. Bulky warrior with a 2h axe? Guy. 1h shield paladin who smites the unjust? Guy. Someone with keen knowledge of the arcane that freezes everything? Female. Cloak and dagger assassin? Female. Pyromancer? Guy. Witch? Female.
Sometimes I mix things up, like the paladin one. And sure, I also take personality into account which can switch it up.
Haven’t played mass effect so no idea about rhe “classes” in it.