This is something that very much interests me.
I have relayed to others, on World Jazz, the St. Louis one, the children follow a sax player whilst beating pots, pans, and boxes in time. What a wonderful way to learn and develop rhythm. Likewise, obtaining a good ear/pitch and vocal strength in choir.
There [b]must[/b] be a study on child music development out there that explains how some people develop into having perfect pitch/good sense of rhythm.
I'm a 10/90 - nature/nurture guy.