"Older?" said the girl Marie.
"Yes, older. It may seem like a fun idea to relive our life again, but if we relive it from that age, we'll make a mess of things. I'll make you... let's say, 10 instead of 6. I'll have to exchange their clothes, but the store's good about exchanges."
Mary went over to the vials and picked out an age 10 vial, which she gave to the girl. "Drink up, Marie," she said.
The girl grew taller, the towel she was half-wearing looking smaller on her older body.
Mary took the vial, put it back to let it refill, and gave it to the boy. "Drink up... I can't call you Marie. How about Mickey?"
"That sounds like a good name," said Mickey.
"If you don't mind being a boy, that is. You have to decide now so I know what clothes to get you."
"I can get used to it, Mommy" he said. "Besides it seems like fun. Learn what the other side is like."
Mickey drank the vial and turned into a 10 year old boy, also wearing a towel.
"I'll let you use the vials," said Mary, "as long as you don't destroy the furniture, or do something you can't reverse. Now I need to leave. I need to get clothes for you two, and toothbrushes and some other things. I never expected to be like this, but now, I'm a mother of twins. And you're brother and sister. I hope you can stay out of trouble until I get back...."