I read a science article about a scientist who wanted to show the probablility there IS other life in the universe. First he isolated 23 factors of the planet earth absolutely necessary for life. The he began studing our current knowledge of the universe to determine how many other planets may contain all of these factors. He gave up when he ascertained that another planet with even 5 or 6 of these factors was essentially a statistical impossibility.
It was a fool's errand anyway. We don't know why or how life formed on Earth. Using my lottery analogy, it would be like a scientist trying to figure out why why a certain person won by analyzing how close the guy lived to the 7-11.