To a certain segment of the male population (say, 90% of it), having two penises sounds like some sort of dream scenario full of functional and sexual possibilities, but the truth behind the very real syndrome is much less glamorous than the high-end porno you’d imagine. It’s called diphallia, and as you can guess, it’s very rare, occurring once in ever 5 to 6 million births. There are currently around 100 documented instances around the world.
For someone with diphallia, it’s extremely rare that both penises are full sized and fully functional (sorry, guys). In fact, in some cases, the second penis is so nonfunctional, the person doesn’t even realize it exists — as with the “buried diphallus” that is hidden from sight. The extent of the abnormality varies and can range from two “heads” extending from one shaft to two whole separate phalluses (one typically smaller than the other). Often accompanying multiple penises are other birth defects affecting nearby body parts, such as multiple rectums, bladders and/or colons, displaced scrotum, spinal deformities, displaced urethral opening, malformed anus and a bladder that forms on the outside of the body. So, yeah, enjoy those two penises, fellas.
The first reported case of diphallia was in 1609, and perhaps the most famous sufferer from the condition was a 19th century Portuguese man named Juan Baptista dos Santos (emphasis on the “dos”). He had not only two penises, but also two anuses and a third leg (insert obligatory penis joke here) that was in fact two limbs melded together into one nonfunctional mass. Both penises were functional, and reportedly Santos could urinate through both simultaneously and would use both during sexual intercourse, switching to the second penis after the first one was done. Supposedly, he had a torrid affair with Frenchwoman Blanche Dumas, who was likewise born with a third leg and two vaginas.
When all is said and done, diphallia is about as rare a condition as penile agenesis, or being born without a penis, so I suppose it all balances out in the end.
(Sources: National Center for Biotechnology Information, Reuters, The Human Marvels, Hypervocal)