How about a story where the virgin birth comes about because the pranksters of planet Klordak happen to nail Mary with their impregno-beam ("Breaks the ice at virginal parties!")? Would that be allowable Christian fiction? I don't think so, even though it would sort of affirm the virgin birth.
Paul said that everything was permissible, but not everything was useful to our walk with God. With that in mind, I'd like to examine the limits of Christian speculative fiction.
Christian writing, fictional or not, should be faithful to what God has revealed. In 2 Cor 10:4-5, Paul emphasized the importance of keeping our minds subject to Christ. Now, ultimately all fiction is speculative: it involves people, places, events, and/or dialog that someone made up. But in speculative fiction, elements not found in the real world arise: aliens, elves, time travel, etc. Can a Christian include such features in his writing? I think so, though only by either ignoring the theological implications (the popular route) or finding theologically sound approaches (uncommon, but more satisfying, IMHO).
There's no shame in not having all your ducks in a row; ultimately we all fail in our attempts to reflect the truth. But even God doesn't get that fussy about details most of the time. Just look at Jesus' parables, especially the one about the merciless debtor (Matthew 18: 21-35). Read it through and reflect on the theology. There are at least two bumps:
1. In verse 30, the just-forgiven servant refuses to forgive the debt of his fellow servant. Instead, he casts him into debtors' prison, which in v. 34 symbolizes Hell. If we're being picky about implications, we'll probably decide that Jesus meant our unforgiveness can overrule God's grace: if I refuse to forgive you, I can send you to Hell, or at least Purgatory, though the same will happen to me.
2. In verse 34, the original debtor is himself thrown into prison until he can pay off his debt, which an overzealous interpreter could take to mean that you can eventually work your way out of Hell.
Was Jesus guilty of bad theology? No. Careless plotting? No. The moral is, "Don't push any story too far!" When God wanted to encapsulate truth in a single place, the result was not a story but a Person. So it follows that stories will have elements we shouldn't take too seriously; yet these are precisely the points some critics seize on to discredit stories and genres they don't like. Don't treat a secondary element as though it were primary.
Finding sound approaches
While no one can be held responsible for every possible implication of their work, we should avoid elements that contradict Scripture (not human tradition). If God took the time to directly state something in the Bible, such as how Mary, a virgin (Luke 1: 27, 34) became pregnant with Jesus (v. 35), I would put that off limits. But if God doesn't directly address something, chances are it doesn't matter so much, and we may speculate. In coming weeks I'll explore what the Bible does and doesn't specifically say about various hot topics, such as aliens, elves, magic, evolution, horror stories, and End-time prophecy. But next time, we'll look at "real" versus "literary."