"What, Mom?" said both of the Maries.
"I can't leave you like this," said Mary.
"It's not my fault," said the boy.
"It is your fault," said Mary. "You must have drank two vials--a female one to split, then a male one."
"And she tricked me into drinking the boy one!"
"But you were the same person when you drank the female one, and you weren't tricked into drinking that, right?"
"Yeah, Mommy," said the boy Marie, pouting a little bit.
"Most of this isn't really punishment, you know," said Mary. "You're more mature than regular kids, but you're obviously not all the way mature and you can get into trouble. I really can't leave you alone as six year olds." She walked over to the vials and neither child stopped her. Then she pulled out an age 13 vial and handed it to the girl. "Drink it, Marie."
The girl looked up at Mary, said "Yes, Mommy," and drank down the vial. Mary took it and put it back, while the girl changed and grew older, her body getting taller and her breasts starting to grow out.
"I feel different," said the new 13 year old.
"You're older," said Mary. "You should be just like me at that age. You're exactly what I look like in the old family album." She glanced towards the microwave oven, whose door was hanging open. "And you're tall enough to reach things. Marie, please? The mess?"
"No arguing, Mom, right?" said Marie.
"Right."
Marie, under Mary's watchful eye, closed the microwave door, then picked up the plate of food and went to the kitchen to wash it. Mary followed, taking the six year old boy with her.
"You can't be called Marie," said Mary to the boy. "How about... Mickey?"
"I like that name!" he said.
"I have to go again," said Mary. "Now that Marie is 13, she needs new clothes again! And Mickey's a boy, so he won't be able to use most of the girl clothes I got. You're both my children now, even if Marie is a little too old to have been my child the normal way. Is that all right?"
"Sure, Mom," said Marie. "I'm you... that means we're family."
"Yes, Mommy," said Mickey.
Marie gave them both hugs and kisses on the cheek and said, "Marie, I'm expecting you to not cause trouble and keep Mickey out of trouble. And if Mickey gets tired, make sure he goes to bed. Both of you can sleep in the guest room for now. I may be a while, since it'll take time to exchange these clothes, and I'm going to eat at the mall. Marie, you remember what it was like when I was a babysitter as a teenager. Well, you should babysit your little brother until I get back."
"Mom, do I get any money for it?" asked Marie.
Mary laughed. "That's what I would have asked. Sure you can, if nothing too bad happens," said Mary. "After all, if it was someone else I'd have to give them money. And if you're going to relive our life as a teenager, you'll need a little spending money."
Mary got some gender-neutral clothes--shirt and pants, mostly--from the bags of clothes she had bought for Marie, and gave them to Mickey, watching him get dressed. Then she went to her closet and dug out some old clothes, some which had shrunken, some which were just old and ragged--and gave them to Marie along with a few other items like stockings.
"Can I use the vials, Mom?" asked Marie.
As Mary watched Marie dress, she explained. "You both have a set of clothes each until I come back. Don't use the vials to do anything that destroys your clothes. Take them off first if it's going to be a problem. Don't destroy the room; I don't want to come home and see an elephant crashing through the floor. Don't split into two again, since we don't know how to reverse that. Otherwise you can use the vials if you're careful. And Mickey, you have to ask Marie first."
Mary turned back and said "Now Mikey, you should remember what it was like being me at your age and having a babysitter. Except you're a boy now. Bye, kids!" Then she left for the exit, and 13 year old Marie and 6 year old Mickey were by themselves again.