According to this CNN article, doctors at Wake Forrest University have grown new human organs from patients' cells.

"In the new procedure, doctors extract muscle and bladder cells from a small piece of the patient's own bladder. The cells are grown in a Petri dish, then layered onto a three-dimensional mold shaped like a bladder.

In a few weeks, the cells produce a new bladder, which is implanted into the patient. Within a few more weeks, the new bladder has grown to normal size and has started functioning.

Atala is working to grow 20 different tissues and organs, including blood vessels and hearts, in the laboratory, according to the university.

"We're not using any type of stem cell population or cloning techniques, but mainly the patient's own cells that we're using to create these organs and put them back into the patient," Atala told CNN.

Because the bladders are grown from a patient's own cells, there is no risk of rejection, as in a traditional transplant."