"Might" be impossible, but the probability (that there exists another planet similar to Earth) does NOT equal zero.
So far, no two snowflakes have been found that are exactly alike. Alike in some particulars, but not all. Same for moons, planets, stars. Similar enough to inhabit as is: perhaps there are some inside the Milky Way; probably not. Similar enough to be called earthlike: probably; similar enough that survival would be likely: probably not. Even with an oxygen atmosphere and liquid water oceans, the vegetation might well be toxic, the animals and bacteria deadly.