I have a new theory as to why some people can't play high notes on the french horn or the trumpet. It has to do with the upper lip having a "widow's peak." Basically, if your upper lip isn't flat or nearly flat, you probably have a good sized widow's peak. If it is large and distinctive (not gradual) then I think that playing high notes will be impossible.

http://www.youtube.com/watch?v=tIhwEbzPwNU

Later,

david