Scientists there are now assessing engineered penises for safety, function and durability, The Guardian reports.

It is hoped the US Food and Drug Administration will give the green light for testing on humans within five years.

Earlier this year, the same team of researchers declared they had successfully grown vaginas in a laboratory and implanted them into four teenage patients.

The new organs were given to women born with MRKH – Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a rare genetic condition in which the vagina and uterus are underdeveloped or absent.