That depends on the message and the world you're trying to construct. World-building might necessarily include other religions, but if you're going to do something based on Christianity, I would (personally, my own opinion) make certain it doesn't violate core beliefs about Christ that might lead a less-informed reader in the wrong direction. If you've never read C.S. Lewis' Space Trilogy (starting with "Out of the Silent Planet"), you might want to do so to get an idea of how he dealt with the concept of Christianity on other planets.
"you're a doctor.... and 27 years.... so...doctor + 27 years = HATORI SOHMA" - RoyalWing, when I was 27
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I could still be champ, but I'd feel bad taking it away from one of the younger guys. - George Foreman