Beach Bum, the answer to your question can only be probabilistic. "Life results from the non-random survival of randomly varying replicators," says Richard Dawkins. Our form of life is based on DNA. Other forms of life, if they exist, will almost surely have a different kind of replicator.
Nevertheless, given that there are far more than a billion billion planets in the universe, then if you assign a very small probability (say, 1 out of 1 billion) to the event of life arising on a given planet, then you would still expect life to arise on about (1 billion billion) x (1/1billion) = 1 billion planets.
That is a strictly probabilistic arguments. It may be that life exists on only one planet (ours), or 10, or 764,934. For now, we don't know.