My daughter is in 2nd class and they began it this year. There was an evening meeting for parents at the beginning of the school year and a note comes home from the teacher at the beginning of each module to let us know which topics are to be discussed along with a form to be signed by parents who want their children to opt out of the class. They don't cover any topics which are inappropriate for the relevant age group (I feel). I don't know if my daughters school takes a different approach to the norm, it is an Educate Together school so parental involvement is maybe given higher regard than some other NS's.