If scientists get approval from the Food and Drug Administration, they will begin testing lab-grown penises on men.

Lab-grown penises will help those suffering from congenital abnormalities, or who have undergone surgery for aggressive cancer or suffered traumatic injury. 

Researchers at the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina already tested the lab-grown penises on rabbits, which appeared to be successful.

"The rabbit studies were very encouraging," Dr. Anthony Atala, director of the Institute, who oversaw the team's successful engineering of penises for rabbits, tells The Guardian. "But to get approval for humans we need all the safety and quality assurance data, we need to show that the materials aren't toxic, and we have to spell out the manufacturing process, step by step." 

Doctors believe if successful the lab-grown penises will be a large improvement comapred to today's remedies for men who medically need this treatment.

If a patient needed this treatment today, doctors would use a flap from their forearm or thigh to reconstruct the penis, Asif Muneer, a consultant urological surgeon and andrologist at University College hospital in London, tells The Guardian. They implant a penile prosthetic to simulate an erection.

"My concern is that they might struggle to recreate a natural erection [with the lab-grown penis]," Muneer says. "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." 

Lab-grown penises are not the first body parts to be bioengineered. In 1999 the first human bladder was lab-grown and transplanted, followed by the first urethra in 2004 and the first vagina in 2005.

The team working on bioengineering the penis are also working on 30 other body parts including a heart and kidney, The Guardian reports.