It's an issue that, understandably, hasn't been touched upon in most superhero properties, but a few have dared to go there. Vincent Ngo's original script for Tonight, He Comes addressed the issue of super sperm quite directly, but his very R-rated script was significantly toned down once it eventually made its way to the big screen as Hancock. However, director Peter Berg did keep some of Ngo's riskier material in his shooting script, it's just that Hancock's sex scene ended up on the cutting room floor.
But of course I've gone ahead and embedded that deleted Hancock scene below, as I was inspired to track it down after watching this fan-made cartoon of The Pro. I actually hadn't heard of Garth Ennis' comic about a superpowered hooker until io9 shared this clip, but now I'm instantly sold on its delightfully taboo sense of humor. If dangerous ejaculation seems up your alley, head over to YouTube to see the full 8-minute cartoon, made by Jimmy Palmiotti. Fingers crossed that someone at Adult Swim takes notice and turns this into a regular series.