Here is a strange idea, but it can work.
Once upon a time the universe was a single thing, solid as a rock, deeply rooted on several laws and which governed the reality but for a series of odd events this universe had fractured itself in 52 versions of itself. And one of this version is exactly a gender reversed one. The guy who numbered all the universes said this world number was 11 (I dunno how he took this decision).
Anyway, here is my rps ideas on this strange and new world:
Teen Titans Go! - The Teen Titans always were aa pool of romance, trouble, some action and a lot of sexual tension not solved... - Ahh, the teenhood... Well here we have a ton of potential couples. From Robin and any different gender, Supergirl and Wonder Lad (or whatever you wish call him) or any pairing you wish to take from them
Justice League - The big names, big heroes and big romances. Nothing better than see a solid friendship get some beneficts