It was a bad day for Snape when Dumbledore told him about his destiny. No, he wasn't going to have to become Voldemort's sex toy again. It was going to be much worse: he would have to bear Harry Potter's child. And there would be no magical turkey baster. He'd have to marry the "one who lived" brat as well as have sex with him. Later, he'd have to change baby James' nappies.
So goes the typical plot of a Harry Potter "mpreg" story, which features male characters getting pregnant. This isn't slash fiction with a twist, though: the point is the pregnancy, not the sex (though there are often lovely sex scenes in mpreg fanfic). Almost every fandom has its mpreg branch, though Harry Potter, X-Files, Lord of the Rings, and Star Trek are favorites. There are even mpreg Spider-man stories, as well as mpreg boy band tales. The manlier or broodier the guy, the better he is pregnant.
Perhaps not surprisingly, most mpreg fanfic is written by women. Some say they love the image of men swelling up into pregnancy, while others like imagining how men would react emotionally to finding themselves knocked up. Thankfully, none of these stories are like the unforunate Arnold Schwarzenegger movie Junior.
Mpreg Fanfic [Mpreg Archive]