They say that gender is as inborn a trait as sex. To reflect that, here's an add-on to any roleplaying game that let's you randomly generate both your character's sex and gender. A third optional step that lets you randomly generate what your character presents as--does he or she prefer to live as a male or female, regardless of sex or gender--is also included. (Frankly, it is our opinion that the third table should be a player decision made as part of the roleplaying process and not rolled randomly.)
These tables assumes the character is a baseline Human with no genetic abnormalities. These tables also assume that the society in which the characters exist value gender identities as part of cultural and social interaction--otherwise, the whole gender thing is pointless.
WHAT IS YOUR CHARACTER'S SEX (Roll 1d10)
WHAT IS YOUR CHARACTER'S GENDER (Roll 1d10)
5-6. Fluid (Roll on the "What Is Your Character's Sex" table whenever it's relevant to determine your character's gender at the time.)
WHAT DOES YOUR CHARACTER PRESENT AS? (Roll 1d10)
5-6. Fluid. (The character is equally comfortable in the dress and roles of either gender.)
If memory serves, we've included rules for characters who can change their sex in Lady Satan 2004 and/or Dynamic Man. We'll have to check--it was considered for one or both, but at the moment we (well, me actually) can't remember what the final decision was. If we didn't... well, it's another excuse for a random table or two for the blog!
For other tables that will infuse more inclusivity into your RPG's character generation system, we refer you to the one that lets you randomly roll your character's sexual preference, your character's race, and the one that lets you generate a disability (can we still use that word?) for the character with a deck of cards.