As someone that has been reading Gender Bender translated Manga since I got into Ranma, I would really like to see what place their reading from to that 99% of gender bender manga has hetro pairing. From what I've seen, there's vastly either lesbian, nothing happening or the translations stopped before something happens. There's very few hetro GB manga out there from what I've seen (And I've seen a lot since I scored every inch of Batoto for GB for a time) (Although that maybe is changing...hmm).
Now, I understand it'll probably be the other way around if you include GB western story as from what I've found, it's mostly GB hetro fetish stuff with very few actual lesbian stories (though from what I've found, there seems to be a surge of GB lesbian for a while now as it seems the LN crowd gets mixed with the GB western crowd).
LN GB stories that are translated also has the same ratio of Hetro to Yuri as Manga, as it's also mostly filled with what I call 'I want to be lesbian' stories.
Edit: Also to add, I also understand that just like western GB, the more....risque....doujinshi out there as vastly hetro with very few same-sex.
Also also, there is very few FTM GB out there in all media I've seen with most of them being a what I call 'I want to be semeuke' stories. So that's a sad state for FTM.