Arguing the scientific probability of extra-terrestrial life is missing the point. The point is that there are lots of things people believe without any proof. Regardless of how sensible it seems, without knowing they can only be beliefs.
I believe in the " possibility " of extra-terrestrial life.
I believe in the " possibility" of the existence of God.
I do not believe in the " facts " of these things. There are no facts, they are only beliefs. Whether it be ghosts, ESP, out of body experiences, astrology, the true nature of Dark Matter, you can believe whatever you want when there is no real knowledge. It's the political arrogance of imposing and coercing beliefs that's disingenuous and harmful.

Hi Nioleon,
I have read there are about a billion galaxies in the known Universe and in our galaxy the milky way there are about 500 billion stars/planets and so far we know of only one with complex cells and intelligence that is on planet Earth,so given that there are a billion galaxies there is possible that there is intelligent life on a billion planets.which would have had time to evolve to become intelligent life forms.and still I would not believe there is a supernatural diety,which counteracts physical laws.

I kind of think this is the same question as "is there a gawd?" "Oooh, look, somebody must have made all this"......
Who cares? How is relevant to me?

For thousands of years, intelligent people have tried to use logical constructs to prove the existence of God, all to no avail.
Using logical and scientific constructs also do not prove the existence of extra-intelligent life either.
No knowledge = no knowledge. Maybe this and possibly that is no proof.
Saying that God is not necessary for the existence of the universe is beside the point. It's like saying blue-eyed people are not necessary for car wrecks. Of course not!
Belief is only belief and nothing else. Being a believer doesn't make you an idiot, being an atheist doesn't make you a genius.

There is no more proof for the existence of extra-terrestrial life than there is proof for the existence of God.

You're statement compares two very different realms: biology and God(s) The existence of biological entities is verifiable from our terrestrial experience, so it's far less of a stretch to expect to find it elsewhere. Saying the existence of God(s) is just as possible, only because of the size of the universe, is illogical because we haven't found any here....

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It seems more plausible now based on recent discoveries that the life we are familiar with maybe didn't even begin on earth. If you believe that's possible, then you have to also believe it's possible life exists or existed elsewhere.

Couple that with the sheer size and commonness of the universe, and the math becomes very compelling. It's very likely life, even life as we understand it, exists, existed, and/or will exist in other places.

God is not a required factor in the equation.

It is a mathematical certainty that life exists elsewhere in the universe. However, that does not mean that life as intelligent as man (if he is indeed "intelligent" ) exists on any particular planet at the same time mankind exists. For most of our (Earth's) history, only microbial life existed. Aside from that, man's interest in "extraterrestrial" life is centered around finding intelligent life and possibly communicating with it which is very unlikely due to the distances involved. In short, they are not coming here and we are not going there...the best we can hope for is radio waves.