Tolerance only works when it's practiced on both sides of the fence. In 21st Century Britain, there are many people for whom the LGBT lifestyle is neither abnormal nor abhorrent. I think the parents should be tolerant enough to accept that. No-one says they have to like it, or even agree with it. But they should at least be prepared to acknowledge the right of those individuals to determine how they wish to live. The school, the State, and the LGBT community itself for that matter, should be tolerant enough to accept that certain groups have values and beliefs that may differ significantly from those which they hold dear. They should be allowed to hold those views, and express those views, as long as it's' not done in a way that causes distress to others. I have to confess that you could write the sum total of my knowledge of Islam on the back of a postage stamp. But if the parents' objections are based on the teachings of their religion, then surely we need to respect their wishes, otherwise we're guilty of religious intolerance, which doesn't say much for our progress towards the multi-cultural society we say we want to live in. If their protests are grounded in misunderstanding of what exactly the children are being told in these classes, then we need to educate and inform, and I think that's far more likely to be successful through the use of an intermediary from their own community.