Bladder Engineers: Making a bladder from scratch:

Essentially, doctors first took biopsies of each patient's bladder tissue to obtain the bladder's two key cell types -- the urothelial cells lining the inside and the muscle cells on the outer surface. Over several weeks these cells were multiplied in the laboratory. Meanwhile, the doctors built a customized three-dimensional shell of biodegradable polymer in the shape of a bladder. Then they added the patient's cells to the shell -- first the inner layer, then the outer muscle layer -- mimicking the order in which the cells coexist in a real organ.

Once enough cells attached themselves, the new bladder was sutured into the patient's defective bladder. To nurture the new organ, the scientists wrapped some of the patients' bladders with a blood-rich tissue called the omentum, which is present in people's abdominal cavities.

They're working on other organs, including penises and vaginas. Now what do you suppose they're planning to do with those?