Linda was happy that the stone had given her a daughter, but she didn't want her son Jon to become a girl. "I wish Jon was a boy again." Nothing happened. Oh, right. Her new daughter's name probably wasn't Jon anymore. "I wish I knew the name of my oldest daughter." The name Jonna appeared in her mind. She sighed. "Okay. I wish that Jonna was a boy again." Again, nothing happened. What was wrong with this thing? It only granted wishes sometimes? "I wish to know why my last wish wasn't granted."
Her eyes went wide, as the information appeared in her head. Wishes couldn't be reversed! So Jon was stuck as her daughter Jonna for the rest of his (or rather her) life!