> What I find rather more annoying is the idea that all alien races can successfully interbreed. I mean, you have more chance of being able to have a baby with an ear of corn than with a vulcan...

Yes, interbreeding across different species is taken for granted in Star Trek. But in the real world, so to speak, you wouldn't even know which of the aliens were male and which female, or whether they had all this male/female stuff to begin with.

I know Star Trek tries to explain it with some mysterious common progenitor race thingy, but it basically stems from anthropocentrism.