Shocked, Karyn realized: everyone had Incan ancestry. In fact, everyone had ancestry from anywhere. No matter what race you are, human beings had intermingled so much that by the 21st century, everyone's ancestry is from everywhere on the planet. If it was just this town, the stone could make Jon into an outsider, but there really was no simple way to keep him from having Incan ancestry and have him still exist.
She needed something that wasn't so simple. Like...
Karyn picked up the stone and made her wish.
"I wish that Jon exists, because he's a space alien, of a type that could pass for human, and has no Incan ancestry because he doesn't have any Earth ancestry. I wish that he remembers his life before and after today's wishes and knows what changed."
Jon materialized out of thin air and said "...mitations." Then he looked around himself in confusion. "Karyn, I'm different... you made a wish, didn't you? I remember my life two ways."
"Yeah," she replied. "You're wearing the same things and your room looks the same, so things haven't changed too much... but you're from outer space now. I mean you're not really from outer space, because my wish is limited by range and it didn't create any new planets, but you probably have blue blood or something.
"Don't you watch Smallville?" asked Jon. "Clark has red blood, when you ever see it, that is..."
"But that's a TV show, Jon. So what kind of space alien are you?"