Infinitesimally low odds. There are infinite different paths evolution can take; we are the product of billions of years of natural and sexual selection of genes that randomly mutated. When, eventually, we find life elsewhere it will more than likely be drastically different than anything we know on Earth.
In Star Trek, so many species in the Galaxy resemble each other because their evolution was guided by ancient humanoids who seeded primordial planets with DNA.
Not being a Vulcan, I'm hesitant to go into the exact numbers, but they would be very, very, very, extremely low. Even assuming a liberal interpretation of the drake equation, we are talking 1 in 1.0x10^(very large exponent) odds.