His mom had wished herself into a teenager, then a five year old. Five year olds weren't teenagers, which meant that the second wish reversed the first wish, sort of. Could this show him some kind of way around the rock's limits?
He decided to try. "I wish that I wasn't a woman." The stone glowed and he felt his body changing. Yes! Jon thought. I can reverse wishes.
Except it really wasn't reversing the wish that made him a mother, because ...