I am not familiar with the public school administration of 25 years ago, or of today, for that matter. I can tell you that I would personally object to a kid using that word in public school just to horse around, or for the sake of saying it, as many kids do. However, were a kid to use that word in biology class, he would be justified, and if I were a teacher, I would actively encourage my kids to use it rather than a euphemism.
Within its proper context, there is nothing improper about it and no reason to be ashamed of using it. It is not graphic in any way and doesn’t conjure any images that wouldn’t also be conjured by a different term. If you are going to sit down and learn about it, you had better not be ashamed to describe what you are learning using real terminology, not couch it in kiddie terms that beat around the bush for no apparent reason.