There's a ray of light for men with congenital defects as scientists have successfully grown penises in laboratories, which are nearly ready for testing on humans.

Per researchers at North Carolina's Wake Forest Institute for Regenerative Medicine, the testing of these bioengineered penises on human beings is only five years away. The lab-grown penises will aid men who encountered injuries to the genital area, suffer from congenital defects or have had to undergo surgery because of cancer.

The lab-grown penises are currently being evaluated for safety and sturdiness. The researchers are hopeful that they can test these on humans once they get the US Food and Drug Administration (FDA) approval by 2019.

The researchers, led by Professor Anthony Atala, have previously successfully tested the lab-grown penises by transplanting them on 12 male rabbits. Post the surgery, the male rabbits were placed inside a cage with a female and all tried to mate. Of the 12, eight rabbits ejaculated and four even fathered bunnies.

The team is encouraged by the success of the transplant in rabbits; however, the need to tread cautiously and be sure of the safety before proceeding on humans.

"The rabbit studies were very encouraging," revealed Professor Anthony Atala. "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."

The researchers have devised a process whereby the bioengineered penises are created using cells from the patient's body i.e. from what is left of the male's penis. This is done so that the person's body does not reject the lab-created organ. The cells are grown for nearly six weeks in culture.

To create the penis' structure, the team uses a donor's organ which is cleaned of the existing cells by deploying a detergent made of enzymes. After two weeks, the cultured cells from the patient are added to the collagen framework of the penis.

Currently, the reconstruction of a penis requires the use of skin from a patient's thigh or arm and a pump is needed to help him get an erection. If the lab-grown penises receive a green signal from the FDA, it would be a step forward for treatments in this area. However, experts are concerned that individuals who benefit from this surgery may not be able to have a natural erection.

The research has been funded by US Armed Forces Institute of Regenerative Medicine, which hopes that the bioengineered penis will benefit soldiers who have undergone injuries in battles.