Perhaps a little off topic (and more than a little naive/ignorant re: other cultures), but I don't believe religion should be taught in schools.
There are too many risks:
Bias (towards the teacher's own religious persuasion);
Misinformation (in regards to other religions);
Harming kids (making them feel badly about their religion if said religion is opposed by the teacher/the other kids/the school itself - so to speak);
Harming kids by scaremongering (as in, the previous point);
Promoting separation between kids/adolescents and, hence, not nurturing the respect of differences between people (and I choose not to use the word 'tolerance' as I can't stand it. "Tolerating" a person/a people/a religion/a sexual identity/etc is intensely patronising - in my view);
The potential to use (or, should I say, misuse) the teacher's/school's religious persuasion to endorse a political stance;
And so on.
Again, perhaps I am speaking from an ignorant place. For example, there are no doubts schools throughout the world in which the one religion is taught and no one is offended.
Furthermore, it's likely I'm speaking from the 'never christened (or otherwise) into any religion as a baby and, therefore, never "indoctrinated" (so to speak)' perspective.
That said, I see religion as a very personal thing - between the individual and their higher power (whomever/whatever that may be). And I don't agree with a person's religion/a person's belief system as sacred as that often is for many, as something that can be (possibly) held up for ridicule.
Finally, in my view, school is for learning the old three r's: reading, riting, and rithmatic.
'Tis all
