For the first time scientists are actually growing bladders and saving lives.

A small piece ( less than the size of a postage stamp ) is taken from a patient's bladder.

Both muscle and bladder cells are then teased out and grown in a petri dish.

When there are a sufficient number of cells, they're layered onto a 3-dimensional mold, shaped like a bladder, and allowed to grow some more.

Several weeks later, the cells have grown into a newly engineered bladder which is then implanted in the patient.

Several more weeks later, the bladder has fully grown inside the body and can function normally.

Seven patients who have undergone the procedure so far report dramatic improvements. Their bladders hold more fluid and they have fewer problems with incontinence.

And, because the new bladders are made from their own tissue, there are no problems with rejection.

Many more studies must be done before growing replacement organs becomes commonplace for organs like hearts, lungs, and livers.