You're referring to a character's sex. Gender is a grammatical concept. And gender identity is a nonsensical concept.
I've played characters of the opposite sex many times, as Dungeon Master. I also often portray characters who aren't even human.
If you want to destroy RPGs, give credence to the critics crying "cultural appropriation" or any of the other SJW/cultural Marxist buzzwords.
You cannot argue with them, they have been programmed to respond to stimuli in a pre-determined manner.
They are doing the jobs of their masters who...
Good descriptive action/favorable circumstances pre-empts move silently/hide in shadows, for all characters.
A thief can roll as bonus to the normal surprise checks, given the circumstances.
This is the perfect plan to create a new "Keep on the Borderlands" as an introductory product that can act as a mini campaign setting and give novice players immediate context for the rules.