Using advanced techniques in tissue engineering and regenerative medicine, doctors in the U.S. are reporting their first successes with lab-grown penises. They've worked in rabbits, and now scientists say they're ready to begin testing the penises on humans.

A group of researchers at Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina are in the process of getting permission from the FDA to proceed with human testing. Their goal is first to work with men who have been injured and need reconstructive surgery, as well as those born with ambiguous genitalia.

Writes Dara Mohammadi in The Guardian:

The penises would be grown using a patient's own cells to avoid the high risk of immunological rejection after organ transplantation from another individual. Cells taken from the remainder of the patient's penis would be grown in culture for four to six weeks.

For the structure, they wash a donor penis in a mild detergent to remove all donor cells. After two weeks a collagen scaffold of the penis is left, on to which they seed the patient's cultured cells – smooth muscle cells first, then endothelial cells, which line the blood vessels. Because the method uses a patient's own penis-specific cells, the technology will not be suitable for female-to-male sex reassignment surgery.

"Our target is to get the organs into patients with injuries or congenital abnormalities," said Atala, whose work is funded by the US Armed Forces Institute of Regenerative Medicine, which hopes to use the technology to help soldiers who sustain battlefield injuries.

One of the big questions for the researchers is whether they can create a penis that is more than cosmetic. Certainly people will be able to use them to urinate, but will they be able to get erections? Urological surgeon Asif Muneer, who is not involved in the research, commented to the Guardian:

Erectile function is a coordinated neurophysiological process starting in the brain, so I wonder if they can reproduce that function or whether this is just an aesthetic improvement. That will be their challenge.

Another question is whether these penises will be made available to transgender men who seek surgery.

The researchers hope to begin human testing in the next five years.

Read more at The Guardian