Sometimes permission is granted, but often it is denied. If you don't want your child to be included, let us know. Controversy erupted, emotions ran wild, accusations abounded, and conflict ensued. It's a conflict-preventer. It is genuinely respectful of ideological and cultural diversity, and it serves both public educators and their constituents equally well.
Parents can thus make a prudent decision based on clear information.
If the families do not affirmatively choose to have the child participate, the child cannot be subjected to the experience. But sex education is hardly the only program which offends many families' values. It would be desirable to expand opt-in to all areas of the curriculum. Opt-in protects teachers, as well as families. Schools that really want to walk the diversity walk can take a major step forward by voluntarily adopting opt-in programs.