Latest update...

I spoke to principal today, who has had many angry parents phoning and visiting him.
The subject used to elective, so there was previously no need to send anything to the parents.
The teacher is new to the school, he had asked a few other teachers whether any letters had previously been sent to parents, they of course said no and somebody told him the school had a kit to make genetalia.. the principal said that he thinks the teacher should have started the class off with discussions to see what the kids already new and to get a feel of how comfortable the kids would be in relation to various issues. The class has now been restructured totally, for some subjects the nurse will take the girls seperatly and in all classes the nurse(female) will be present.
The prinicpal hasn't yet seen the questionare re. the masturbation but will be having a look at it,I made it very clear that if it comes up in class as a subject that I would take the matter further. It's one thing if one of the kids has a question and the teacher answers it, but whole different kettle of fish if it is actually taught.
Apparently the principal has had words with the teacher, so hopefully there will be no more surprises
I have asked for a lesson plan for the rest of the term to be mailed to me, which he is happy to do.
Just hope that this is the end of it all.