@EmeraldLagasse
Because nee-San technically translates to "big sister" and shounen wants to kiss her. I am sure you can see the unfortunate implications to making the story be about a boy that wants to kiss his big sister.
@starburst98
But even if you change boy to shounen (which is just the same but in different languages) they both still imply that a boy likes his big sister
Shouldn't the "Onee-san" part be changed instead to remove that implication?