They were just way to cute, adorable and innocent for that, in the first season, the spawn of Satan was the product of an incubus, Tate, impregnating Vivian Harmon. Tate was a ghost by the way. I just don't see how this would happen with a regular couple without supernatural intervention. BTW the whole time travel aspect negated everything that went down in the Murder House, particularly with Moira, in their quest to defeat Langdon, however they may revisit it when the next Anti-Christ is old enough to destroy the world. I do like that they made Langdon an idiot easily duped by a pair of tech guru's in Silicon valley.