Io9 reports on a conference in which at least one panel explored the ramifications of intelligent life on other planets and Christianity, asking whether Jesus would have gone to other planets or if the Terran Jesus died for the sins of everyone in the multiverses or if perhaps mankind is uniquely saved.
While the io9 report makes too much out of the government funding given to the conference (which had nothing to do with a particular paper presented in a particular panel), the question is a fair one theologically.
Christians faced similar questions when in the Americas they decided whether or not to teach their religion to the natives there or to their imported slaves. The Spanish position originally was not to convert the indigenous peoples as that would then imply they had souls and therefore could not be enslaved quite so ethically but once that genie left the bottle thanks to the work of a few missionary priests things went into overdrive and the assumption was that everyone was saved if they believed.
Another approach is the Mormon theological position that Christ appeared not only to the Israelites but to the folks on the other side of the planet as well.
I would imagine that when – not if, if you will – we encounter extraterrestials then there will be those who hang onto the superior humanity gambit and those who work at conversion.
Of course, I assume that a few alien religions – assuming that they have them, which I suspect will be the case – gain ground among humans as well . . . evangelical Klingons building their own megachurches on Terran former holy sites. Same old, same old.
Of course, it’s all moot until well after First Contact . . . more like sixth and seventh contact for this sort of question to even be an issue.
In the meantime, folks asking this sort of question are perhaps preparing humanity for the inevitable discovery of extraterrestrial life, if not intelligence, and the question of whether or not our Terran deities should be reframed to multiversal hierarchies or if we should consider them merely Terran tribalesque constructs no longer valid for universal civilizations.