My mom and sis were both cheerleaders. My dad and bro were both football players. I was neither and felt like a bit of a black sheep growing up!
Cheer leading used to be kind of fluffy and now it is often seen as a "real" sport. At some schools, it's a lot more athletic and competitive than it used to be. (especially since a lot of former competitive gymnasts end up making a team.)
I doubt my daughter will ever have the grace or coordination to do it, but if she did, I'd support it. The cheerleaders I know from high school have generally gone on to be pretty successful in life, and are nice people.