Creationizm in school?

I do beleave i asked this once before back in august but im asking again because this topic has showed up on my old highschools school board meetings.(there always so much fun...>.< not!) If Evolution is aloud to be taught in school why cant creationism be taugh also. its like the teachers say before they begine the lesson on evolution. "you dont have to beleave i just gotta teach it" if thats the case why cant they teach creationism too? Some Call Creationism a science others a religion...the same goes for evolution.... no one is saying the teacher is has to give his personal opinion on the subject. and no one is saying the kids have to beleave it eithor so why is it that to this day it is still not taught in our school systems?

"They took your comandments off the school house walls. they say its a crime to even pray within the halls. but bless the child that lets you in and knows with out a doubt. once you live inside a heart they cant take you out!"