Is it wrong to date your teacher?

A relationship between a student and a teacher should be acceptable as long as they maintain their professionalism within the school. He or she might want to start dating, but students shouldnt want to date a teacher. The reason for this is the age difference.

Can parents say no detention?

Parents cannot overrule the school when it comes to detentions. You have no legal right. If you refuse to let your DS attend, then the school can escalate the sanction, e.g. an internal isolation.