If you want your kids to know about God, then talk to them about God yourself. Explain to them while school talks about the science of evolution, there is another take based on belief of God. It's not the schools place to teach religion. They already have too much other crap to deal with.
But to play devils advocate for a second, if schools were to teach religion, which one? Who says your belief is actually the right belief? Not to mention, you also open up a whole can of relgious persecution for those who don't follow the supposed "right" religion.