What if Superman had always been a woman?

[Not really the point of this post, but I went completely insane today and cleaned the entire freaking kitchen (including washing all the dishes, mopping the floor, taking out the trash, and cleaning the stove, for fuck's sake), went to the store, and cooked a gormet fucking meal for dinner: tarragon chicken, steamed asparagus, candied carrots, French bread, white wine, apple crisp with cream for dessert. INSANE, I TELL YOU. But delicious insanity, at least. :D]

I was talking to my mom the other day about fandom, as I occasionally do. In this case, I was explaining some of the weirder subgenres that spring up -- wing!fic, genderswap, bodyswap, AUs, etc -- in particular always-been-a-girl fic, because I've been enjoying the hell out of idyll's always-been-a-girl!Bob fic (which I will once again say is awesome and everyone should read). Anyway, I babbled on about always-been-a-girl fic and the cool things you could do with examining gender dynamics. Then my mom did the "make an exemplary statement in summation to show understanding" thing, and it was TOTALLY AWESOME and I had to share. Because she said:

"Right, like always-been-a-girl Clark Kent."

And I said "...OOOOOOH."

Because that's a REALLY COOL IDEA, OKAY? It's different from Supergirl, or Wonder Woman, or any other superheroine, because Superman is the iconic hero. And what if he'd been a she? Can you imagine? I mean, besides the effect it would've had on the story itself, Superman is such a powerful figure that it would've actually changed the world, I think. What if the original superhero had been a superheroine? What if all the super-powered women who followed weren't just considered slightly weaker female knock-offs of an iconic male figure? Do you think it would've had the same impact? Do you think people would've been as struck by Supermanwoman? Do you think it was even possible for someone to have created such a strong female character in that day and age?

C'mon and talk to me about this, y'all. (poisonivory, I'm looking at you in particular.) What's the first thing you think of when I say "always-been-a-girl Clark Kent"?