On the one hand I get what you're saying, but in the other hand I feel Luke saying "their gender isn't really important" is really not understanding what OP is saying.

I recall a similar story, I wonder if they were the same? I think the one I read about was someone who had it read to them as a child and their dad always changed the genders when reading aloud and the daughters didn't realize until they were older and read the story themselves for the first time.