Karyn looked at Jon through angry yet immobile eyes.
"Sorry Karyn" he said sympatheticly. "It's not my fault... i can't tell you why or i'd change."
Jon knew it was more complex than this... After Sarah wished Karyn would change she made another wish on Jon. She wished he was a girl before so he could feel the change he'd face if he thought of changing someone. But faced a problem that when changed against his will Jon was constantly thinking of getting help which would have kept him from being a man at all. So she wished that his demo change ended and his changing curse was put on pause until he actually tried telling someone. Then she enhanced his male body.
After all, what Sarah wanted was Jon as one of the men she won over to serving her, not jon as a permanent girl. She just wished that wishes were reversible so she could change think into try to tell.
