Not unless you have entered a cheat......
The cheat is "testingcheatsenabled true" (without quotation marks) into the blue cheat box you get when pressing control alt and delete at the same time. Then you shift click on the kid (or any age except for newborn) and click "edit sim in create a sim." From there it takes you to the create a household which will let you change your selected sim's features.
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Get the sims to WOoHoo
You can't change your sims height..
Molly Sims has 3 children
no kids can't kiss
In the Sims 3 to change any ones name you go to city hall and select the option change Sims name and then you choose which Sims name you want to change.