What is the problem with teaching religion in schools?

[Matt]

Just about any half decent public university has lots of religious courses for students to take, so why is it so controversial to allow elective religious courses in public high schools? If it is ok to take these classes at a public university, why can't high school students that are interested take these courses too? Why deny them the right to learn something they might be interested in?
Shinkirou, you don't think your tax dollars goes to public universities? are you an american???
anautumnrayne, I was thinking more of a class that focuses on the Old Testament, another for the New Testament, one on Islamic Studies, etc. Similar to what colleges have. What would be wrong with that?