"An Amish boy and his" joke

An Amish boy and his father were visiting a mall. They were amazed by
almost everything they saw, but especially by two shiny, silver walls that
could move apart and back together again. The boy asked his father, "What
is this, Father?" The father responded "Son, I have never seen anything
like this in my life, I don't know what it is!"
While the boy and his father were watching wide-eyed an old lady in a
wheel chair rolled up to the moving walls and pressed a button. The walls
opened and the lady rolled between them into a small room. The walls
closed and the boy and his father watched small circles of lights with
numbers above the walls light up.
They continued to watch the circles light up in the reverse direction.
The walls opened up again and a beautiful 24 year old woman stepped out.
Smiling, the father turned to his son and said, "Go get your Mother."