Like a certain wolfman, the time has come to ask: Do Aquamen have gnards?

Yes. Men have gnards. Fish have gnards. It goes to say that Aquaman does indeed have gnards. However, a penis is a trickier issue.

Surprisingly little has been said about the mating habits or anatomies of many of our favorite mermen and -maids. Much depends on the origins of the mermaid, are they aquatically evolved humans (or would that be de-evolved)? Or are they some unknown intelligent subspecies of fish? A mutant of some kind? A human/fish hybrid? If we examine the classic mermaid imagine, the head and shoulders of a human with the bottom half of a fish, this would definitely suggest both fish genitalia and most likely fish mating (or doing it fishy style). However, the merfolk of comic books—Aquaman, Tempest, Namor the Sub-Mariner, Aquagirl, Namora, Lori Lemaris, Aspen, Abe Sapien—are a little more human looking and harder to make that call.

Most male fish do not have penises, their anatomies being very similar to those of the female fish (at least, on the outside). If you didn't know or slept through 5th grade biology, fish reproduce externally. The lady fish lays the eggs and the male fish comes along and fertilizes these eggs. And much like Julia Roberts in Pretty Woman, there's rules about no kissing or eye contact. This is why tuna is called the high class prostitute of the sea, but I digress.

We have to imagine this is how merfolk spawn, too. However, oceanic mammals do have penises, and if anything a mermaid or -man would fall into a mammal category. This would suggest more traditional internal sexual reproduction. However, since most merfolks have features like gills (The original Golden Age Aquaman for example originally had gills), one would have to consider any entirely different evolutionary track apart from humans.

Both Aquaman and Namor are Atlanteans (both royalty, too [aren't there accountants or dishwashers (dishunwashers?) in Atlantis]), however, the Atlanteans of Marvel comics are a little more like squatters in the ruins of the Atlantis. Homo mermanus are a separate offshoot of humanity that simply stayed in the water, and are not people of Atlantis who magically grew gills. This definitely gives Namor a higher chance of having fish equipment. With no penis, Namor's spacious speedo would most likely then be filled with sea shells and broken hypodermic needles. This would also explain the often wielding of overly large tridents or fearsome hook hands... someone's overcompensating.

Both Sub-Mariner and Aquaman have backgrounds wherein their daddy's were drunken sailors who got scaly with a friendly fish lady (which would also call into question their "royal" linage). Half man, half merman equals about a quarter fish (a merman is already half fish), which gives Namor and Aquaman about a 75% chance of possessing human genitals. Those odds are good, but not definitive. This sort of genetic roulette would also bring rise to a third option: the fish/man hermaphrodite.

For the sake of science, I turned to the source material. I spent several weeks (this is why there's been so few posts... yeah, that's why) combing through the National Comic Book Archives and finally found an answer:

And there you have it—manginas. Disgustilating. And remember, kids, Aquaman isn't lame because talking to fish is a useless power to have during a bank robbery (and most every world domination type situation), Aquaman is lame because he has no penis.