The reference in the newsletter to kids saying things in the classroom that must have came from discussions at home was interesting....but was it handled in the best way? We are left to guess at what came up, in what context, and at what point the parents were called, but it seemed an odd thing to fill up the newsletter. Not sure if it is a "little Johnny" story about where babies come from, or something else, but the more I think about it, the less I am sure what the intent is to be.
Not talk about the "issue"? Hmm...doesn't seem like that makes a lot of sense, especially if I want to exercise my rights as a parent to teach or inform my child of "issues" before society gets their chance. Talk about it and tell the kids not to tell anyone? Again, depending on the issue, it may well go against my wishes.
The issue probably does need to be handled delicately, and on an individual basis based on the kids, the teacher, the parents, and the issue, not mass mailings warning you to be careful on what you discuss in your home.