Rare medical discovery reveals a 78-year-old man had three penises. According to experts, supernumerary penile formation is extremely rare, occurring in only 1 in 5-6 million live births. The anatomy was complex, with the organs developing within one of the penises. While the cause behind this condition is unclear, it's thought to be linked to genetic mutations affecting androgen receptors during development.

Source: https://www.popsci.com/science/man-with-three-penises/