True, but if you're human and you're here now, there must have been a decently similar course your universe must have followed in order to produce you. Therefore I'd think it decently reasonable there's a chance at least one other species evolved on another planet, especially considering in any universe it's considered a biological miracle that humans evolved at all.

[He takes a thoughtful sip of his drink. Infinite universes in which humans existed and infinite universes in which they didn't. Sometimes the sheer number prospects were mind boggling.]

Yeah I can't remember how many member species are part of the Federation but there's a few. [And xenoanthropology is hell. Kirk can't imagine what kind of training Bones had to go through in order to get his license to practice--he knew they'd have to be able to practice medicine in at least a few of the other species most prominent in the Federation.]