The thing with videogame characters is that they tend to be really undercooked, and people don't take the time to really flesh them out. They don't treat them with the respect that a writer writing characters in any other medium would treat their character.
I think it's essential for writers to be involved in the recording process as things can often go wrong in this area. Voice actors are all too often presented with a wad of XL sheets, no proper character notes, context or reference and are just expected to perform.
I like to make all my characters interesting. Be they male, female or creatures unknown.
By the time a writer comes onto a project (if they're being hired as a contractor) the main character has usually been designed, as that's always done during a project's pitching stage.
Generally I wouldn't accept work on projects where I didn't agree with the sensibilities behind the main character.
I think it would be a great challenge to work on a military game which featured a female lead character. Since female soldiers are now being allowed on the frontlines, we're actually in danger of reality overtaking games!