Sex education in schools

is a tricky subject. I am sure that there will be some curious individuals who will find this page and be ready to rant and rave at me. I'll try not to rant and rave.
There was a Guardian piece on the topic. It was written in response to criticism of a teaching guide called "All of us" put out by the "Safe Schools Coalition". If you want to follow it up put in those  search terms and follow the links to a range of material and opinions.
I am wondering if schools have changed. I went to school with students who were undoubtedly sexually different. I don't remember them coming in for any more teasing, bullying or abuse than anyone else. I came in for at least as much, probably rather more. Being "the head's kid" didn't help in some places. Perhaps students in rural areas take such things on board more easily? Were there students hiding their sexuality? Possibly  -  but in a rural area it would have been hard to hide. 
Even in my boarding school I can't remember the couple of undoubtedly "different" students being ostracised or subjected to bullying and abuse. If other students were hiding their sexuality I was not aware of it and I don't think they would have needed to do it.
All of that was a long time ago. We didn't have sex education lessons at school. Parents were supposed to teach you. My mother tossed a book to me with the words, "Everything you need to know is in there." My paternal grandmother, brought up on a farm, explained some more. (No, the book did not tell me everything I needed to know.) My brother had the same book tossed to him and, I suspect,  a talk or two with our father.
So I suppose I am wondering why it has now become a "problem", a problem so large that it needs special attention in sex education classes in schools - and not just one or two lessons but a whole series of lessons that might well cover a term. Why has it become something that needs to be discussed in great detail? Why does the teaching material require responses to questions about intimate and personal feelings, especially at a time when many young people feel sexually vulnerable?
If we are to teach sex-education in schools - and it seems necessary as parents now apparently expect it from schools rather than themselves - we should talk about a diverse range of relationships.
It should be done in a calm and compassionate way. We should be saying, "Sexual attraction is personal, not political. Your feelings are your affair. It can be complicated. Take your time."
Are we just trying to get them to grow up too fast?