Actual answer from someone who’s been reading the comics for thirty+ years: 
But here’s my own nerd-reasoning: The Man of Steel, Woman of Kleenex essay is based on the idea that Superman has an inhumanly high base level of strength that he needs to consciously tone down in order to exist among humans. And in some stories this seems to be true, like with the occasional gag about a super-sneeze. But a lot of the time it’s written as though his base operating level of strength is human, and anything beyond that is due to conscious exertion. Which is why he doesn’t cause gusts of wind when he blinks or minor hurricanes when he farts.
It’s like speaking. Everyone has a normal operating volume, and we can choose to whisper or shout. And some people can whisper quieter or shout louder than everyone else.
So unless he’s trying to force it out, we can assume he jizzes just like everyone else.
The question fans were asking (which hasn’t been answered) is: How could Jon even be conceived when it had been established for about thirty years that humans and Kryptonians couldn’t naturally interbreed? Kryptonian genetics is supposed to be orders of magnitude more complex than human. The only successful human-Kryptonian hybrid before this was a clone made from a mix of Superman and Lex Luthor, and every one of the other clones from his project degenerated into Bizarros and died. Like a lot of things in comics (e.g. the question of how no-one has his fingerprints on file), they’re just saying “It works like this now” and we’re all just rolling with it 'cause why not?
