As far as I can tell, only two reject it outright--some of the more fundamentalist sects of Islam and some of the more extreme varieties of rural North American Evangelical Protestantism. I'll let you draw your own conclusions about that telling little symmetry.

The RC church crossed that bridge a long time ago, accepting both evolution and the possibility of extraterrestrial intelligence. I believe the Vatican has an official position on both. However, the question of whether alien souls are equivalent in god's eyes to our own is usually postponed until some future time will require it be answered.

I wonder if anyone has an official theological position on a hypothetical artificial intelligence, perhaps one created by a long-vanished alien species. Or what about a hive mentality or group mind, a distributed intelligence capable of building spacecraft and radio telescopes? Science fiction has postulated several different alternatives to a sentient entity modeled on our own. There's no telling what kind of variations on consciousness are out there. Perhaps every single one is totally different to ours; you know, alien. And of course, there might not be any at all. We may be the only one. Perhaps we may be the only one that ever was, or ever will be. There is a lot of circumstantial evidence suggesting the existence of life in space, but absolutely none to imply that life might be sentient or evolve any kind of intelligence. And certainly none to suggest it might be technological.

I suspect that any evidence of an alien species, even one now long extinct, would have a profound effect on the believers, although I'm sure the religious leadership would quickly devise a doctrinal explanation that would fit in with their existing dogma.

Its too bad our conservative friends have been so shy about contributing to the Zone lately. I would love to hear their arguments about the economic systems employed by alien races. After all, on our planet, the first spacefaring civilization was Communist.