Take a spoonful of dirt on Mars and you won't find any evidence of life whatsoever. The question isn't settled but so far Martian soil appears to have all the characteristics of being extremely sterile. And so the question of life elsewhere int he universe is still a very open question. There are extremely compelling arguments and bunches of evidence supporting both sides of the argument right now.
I always wondered why the landers haven't gone closer to the polar ice caps. Since it's a general assumption now that water is necessary for life, if you're looking for microbes or other such things, why not go where the water is?
If the soil of Mars is indeed sterile, and has always been sterile, then so far that adds up to 50/50 life over uncountable googolplexes of worlds.