Growing up Skipper: a doll made from 1974 to 1977 by Mattel. You cranked her arm backwards in a circle, and her breasts grew. She would also gain half an inch in height. I had this doll, in its red leotard and wrap-around red and white checked skirt.
The original Skipper, Barbie's little sister, was made without any breasts.
I see Growing up Skipper as a progressive and feminist attempt to teach pre-pubescent girls that their bodies were about to change. A nice try, but I think most girls realize that they are going to grow breasts. It's the menstruation part that is mysterious, and there's no Barbie doll explaining that, at least not yet.