I attended a Novus Ordo Catholic school for my Jr High years, and we had a sex ed program. However, many of the lessons included Church teachings on those matters. We were taught that sɛҳuąƖ interactions were between a man and a woman and that we were to abstain from sex until marriage. Never did we color pictures depicting genitals.
Nevertheless, there is no reason why a school should give sex lessons in a mixed sex setting, or under any circuмstances.
Teachers have no right to usurp the role of parent and each child should be instructed by a parent of the same sex (Sometimes not possible these days) and individually.
Another person may take on the responsibilty only at the request of the parent/s. This is Church teaching!