I guess the grass is always greener on the other side. I'm 5'8". I wish I were taller.
Footsoldier - Genetics is like a big game of Texas Hold 'Em - you get the hand you're dealt and that's that. Your brother may just be a fluke. There are several online calculators that allow you to predict height based on your mother's and father's heights, plus or minus 2" or so. They are fairly accurate.