No one but me calls her Isabella. They just call her Sybil's clone, and I wasn't even supposed to be there but I snuck in when Dr. Goodheart was talking to Mummy and Daddy, and I saw her.

I never said that I stayed there behind the curtain that day I met Isabella. She was just sound asleep in her jelly bed but I went over close and smiled at her. Her eyes stayed closed but I know she smiled a little bit at me and I told her I would never, never cut off her leg even if I lost mine.

At my school we all have clones. We learn about them in science. They're called our Genetically Paired Medical Auxiliaries.

The kids in public schools don't usually have clones. They sometimes get them when they're grown up, just in case, but they're not like ours that are exactly the same age as us.

When I was just a nursery school kid, I asked my mother if I could invite Isabella to my birthday party, but she said don't be silly, clones are not real people. They're just depots for medical purposes. Couldn't all the kids bring their clones, I said, like the nannies. They could have their own party like the nannies do.

But why, why, why, I asked. I tried for days, and cried, and even locked myself in my room. She's a little girl, just like me, I said, but they said it was impossible and could never be.

Ever since then, on my birthday, when the house is full of whispers and I find little snippets of gold paper and ribbons in Mummy's wastebasket, I think about Isabella. Oh, I don't mean I think about her all the time, but on my birthday, our birthday, I never forget.

Today is my sweet sixteen party. I have a dress that's all white and floaty and I'll have fresh flowers for my hair. The workmen are putting up a big canopy on the side lawn for dancing and delivery trucks have been rushing in and out all day, but I have remembered Isabella lying there naked in her jelly.

I know a lot about clones now. I did them for my Science Fair project last year and got an Honorable Mention. I've learned to act casual about the whole subject so they don't stiffen up and act suspicious.

I guess I know now how silly it was to want Isabella to come to my party. Clones' minds are not awakened. They have never spoken. From the moment of their conception, they are drugged to sleep. Every day, machines rotate them, push their arms and legs up and down and around and around so that their muscle tone will be good when we need them.

If I want to, now that I am married, I can have Isabella carry my child. That way, I won't get stretch marks or saggy breasts. My husband will love me more if I stay beautiful. Secret thoughts whisper to me. Is it possible he will love Isabella more when she is big with his child? I must make sure he never sees her. It's not considered really nice, anyway, to see someone's clone. They say our clones always look younger than we do, and more beautiful. If science could transfer our brains, we could stay ever young and beautiful, moving to a younger body every few years.
    
When she is old enough to know, will my child yearn to see her birth mother? Will she love her more than me? There is no word in our language for the child of a clone. Auntie Isabella?

What will happen if I die? Will my husband come and take Isabella away to be my memorial? Will he take her from her bed of jelly and put her in my bed?

If I grow old and have kept my promise to Isabella, will she come to lie beside me in my walled crib and keep me warm?