The acronym Mpreg derives from "male pregnancy", a concept originating in the sci-fic fandom but widely distributed throughout fandoms.
In Supernatural fandom, mpreg stories generally fall into one of three categories:
- crack – where the author plays with the absurdity of the concept
- domestic fic – where the two characters involved have a baby and make house
- dark mpreg – where the pregnancy arises from demonic or other supernatural impregnation, and the offspring is not entirely human.
- Winchester Mpreg community on LiveJournal.
- SPN and J2 mpreg rec list by billysgirl5