I think that whilst some people may have a natural advantage in being born with good timing, anyone can develop good timing with practice and time.
That said, I seem to have great timing!
Shame I can't ear-play too well...
Interesting comment. I've known a lot of musicians with very acute relative pitch or perfect pitch that had really horrible sense of time and tempo. AND..... players who could semingly remember exact tempos (I tested them with a metronome) and had great time that couldn't find a pitch to save what soul they had left.
IMHO we all have good timing and good pitch, but its what we choose to pay attention to that makes a difference. We all hear our voices go up in pitch at the end of sentence to indicate a question. And people tend to walk in steady tempo, and almost everyone has a steady heartbeat, so the rhythm is in there.
In my experience as a music teacher I've found that everyone seems to have one of these things stronger than the other, and in most cases with some practice and work, the other can be brought up to near the same level. The age that we start working and the intensity have a lot to do with the end result.