Honestly, it's completely false that you can't be taught to sing certain notes. The notes will come easier to certain people, but I (personally) believe that just about anything can be taught, it just takes some people longer to learn than others.
When I was a freshman I was told that I was a bass, and that I always would be. I started taking private lessons that year and my voice teacher told me I was a tenor, but didn't know it. Freshman year my low note was an E two octaves below middle C and a middle E. My senior year my range was a C two octaves below middle C and a high Ab. Now, as a sophomore in college, my range goes from a B two octaves below middle C and a high C.
Moral of the story is that a Bb isn't something that's going to happen overnight. It took me almost 6 years to get comfortable up in that register. I was told I would only ever be a bass, but now I can sing bass, baritone and tenor all equally well.
And Bradley gives a very accurate technical analysis of singing in the upper register for men.
Eeeeeeyyyyyyyyaaaaaaaannnnnddddd aaaaaaaiiiiiiiiyyyyyyaaaaaammmmmmmm teeeeeeeelllllliiiiiinnngg yyyyooooooouuuuuuuwwwaaaahh...
