Only parents should teach children sex education. Period.
Not even Catholic groups should do this. It is not the business of other people outside of the authority of the parent to teach children intimate things, even theology of the body groups.
In fact, I think strangers have no authority from God to teach sex education.
Only parents have been given this authority from God.
And, I again mention that Blessed Paul VI's and St. John Paul II's desires for the deaconate marriages were that they would accept Josephite marriages, and same with married priests. Sadly, this ancient rule has been bent by local bishops. Deacons should not be teaching sex education. Period.