Most Helpful Guy
I'd say it's pretty probable..
I mean, if you look at what life really is, at its most basic form, that would probably be the result when life began, it's just a chemical interaction, right? Self-sustaining and self-replicating molecules. Shazam! Secret of life right there... ;p
So if we accept that (and good luck arguing against it), then any place that would fulfil the necessary ingredients, will have the process of life emerging. If the requirements are met (planet is in the Goldilocks zone, certain set of organic compounds are present, add water and energy), then like any other chemical reaction, life WILL start. It's inevitable. It HAS to, like mentos and diet coke HAS to make a fountain. It's just what it does...
Plus, we even know that organic compounds can be found on meteorites, so we know the possibility is out there. Stronger still: the beginnings of life may have been on those meteorites and have bombarded down on earth one day. In a way, WE could be the aliens :O. (also: look up Europa, the moon, as it's speculated that there might be life there)
And isn't that just cool? Isn't that humbling, in a way, to know that we once were those simple things? That we still ARE these things, in a way? To know that we are the intermittent result of a process emergent from the very properties and workings of the universe itself? As Carl Sagan said: "We are a way for the universe to know itself"... Kinda gives you goosebumps even thinking about it, doesn't it?
As for god having made us in his image, therefore we are the only ones? Blehh.. Religion.. It's one of those claims that's so out of touch with reality you don't even have to debate it (hell, I sometimes can't even tell if the people claiming it are trolling or not).
Bottom line is: we've done the science, we have looked (and to this day continue to look) at reality so very deeply that we have a much better idea nowadays of what happened and what might have happened than any religion can claim. You can hardly argue it, in as much as you can argue a thermometer about what temperature it is.
I'll just quote Richard Feynman here: https://www.YouTube.com/watch?feature=player_detailpage&v=cRmbwczTC6E#t=213s
And us being visited? I'm pretty skeptical about that. I've seen no credible evidence whatsoever, really, and the stories that people do tell, the so-called eye witness testimonies, sound like a science fiction story, and a pretty bland and uninteresting one at that.. Hardly something highly advanced civilizations would do, I'd imagine.
Anyhow, I'll just finish off by leaving this (Carl Sagan is a Boss; if you have time, watch the entire series... the guy is so eloquent and catchy in expressing his ideas and passion it's unbelievable, plus the music and visuals have certainly left me with a lump in the throat multiple times): https://www.YouTube.com/watch?v=EHuve33yOVY&feature=relmfu (this one happens to be on SETI, so it's on-topic, don't worry ;p)