Two of a kind

"Coming, uh, mom", John said. He was worried about what could have happened to Karyn and was looking around all over to see if she had been turned into something when Karyn's, now his, mother added,
"And you too Kim. Hurry up and finish getting ready" as she knocked on the bathroom door.
Just then the bathroom opened and Karyn, now Kim came out. She looked exactly as she always did and Jon realized what had happened. They were twins.