Definitely a possibility, but not sure that the probabilities are very high.

One may think extra-terrestrial life is likely because there are so many stars out there. On the surface this seems reasonable, but when you look deeper into the issue, there are many conditions that need to met for life to get a good foothold, some of which include:

1. Star type (Giants or Supergiants are not good choices as they don't last long enough astronomically speaking for life on planets around them to develop)

2. Position of the star system relative to the host galaxy's centre (near the galactic arm for spiral galaxies are better since most galactic centres harbour supermassive black holes)

3. Planet type (planets with strong gravity stand a better chance as they can hold onto their atmospheres better)

4. Planet core type (the core type affects the existence and strength of the planet's magnetic field, which is vital for keeping out harmful radiation from the host star)

5. Presence of large neighbouring planets (this is helpful for "taking hits" from asteroids for the planet which life develops on)

6. Distance of the planet from the host star (too close = too hot, too far = too cold)

7. Presence of a moon for the host planet (this helps offset the side-effects of the gravitational pull of large neighbouring planets)

Not saying that life on a planet cannot develop without these characteristics, but it will be harder. Life can be quite hardy and survive in the most unlikely of places, so the attitude I take is "keep an open mind, but also look at the evidence".

I think so far there has been more than 200 extrasolar planets discovered, but all of them have been deemed to be most likely unsuitable for life.

And by the way... the presence of water does not mean there is life.

Regarding UFOs, from memory, when I did research on this, there were around 2% of all sightings in the world that could not be explained despite scrutiny and analysis by experts (astronomy, aerial phenomena, etc.). In number terms, that translates to over 10,000 sightings (conservative estimate).

UFO research authorities such as Jacques Vallee tend to think that this means there is something to the sightings than just "fluff" or mistaken identity.

Me, I've never seen a UFO before, and probably never will. But, I remain open to the possibility that UFOs are indeed evidence of other lifeforms (either extra-terrestrial or the inter-dimensional type). At the moment though, there isn't enough evidence to convince me there is.

I personally don't get too hung up on this ... doesn't affect really my life.