In preparation, I remind myself of the content of the programme and materials used by teachers. I have the Scottish Executive document Sex Education in Scottish Schools at hand, ready to wave at the assembled audience, and I copy relevant pages from national guidelines on science and health education as hand-outs to explain the “why” element of the programme.

The “how” part is quite straightforward too. I explain that we adopt a no-nonsense approach to sex education, as we do in any other area of the curriculum, after allowing for the anticipated, initial reaction of embarrassed giggling and nudging.

The “what” is a little more tricky. I deliberately show the parents all of the personal bits of the videos, so as to prepare them for what may come their way at home when they least expect it (and probably when they have grandma around to babysit).

I offer advice, based on other parents’ experience, on how to explain the mechanics to young children, if they are asked. Or how not to, in the case of the expectant mum who told her pre-school age daughter, “Well, you see, Daddy has a snake ...” A lifetime of disappointment guaranteed there.

I have become quite blase about the animation of sexual intercourse and masturbation, but I did notice that the grandparents who were standing in for parents at the meeting this year appeared to be in a state of shock.

I refer to “we” throughout my talk to parents, but of course I really mean “they”, as I personally have nothing to do with the actual delivery of this highly sensitive subject.

I am full of admiration for teachers who do not blanch at the prospect of dealing with enquiring minds, which have been fuelled by storylines in soap operas and media headlines, and discuss various relationship scenarios with a great deal of professionalism and good humour. However, I do reassure parents that there are some areas into which no teacher will venture.

We provide a post box for those children who are too shy to ask anything in front of the class. One of our more mature teachers found a question about oral sex. She came to me in a panic and I assured her that this was not an area for discussion and that she should ignore the question. The next week she found another card from the same child which read: “You never answered my question about oral sex.”

I heard of a middle-aged teacher in another school who, when asked what sexual intercourse felt like, merely replied: “I don’t know.”

The student teacher on placement with her commented later that she greatly admired this response and would use it herself to handle a similar situation. “But, Miss Brown,” said the spinster, “I don’t know.”

I have delivered this talk to parents for many years and the basic content has changed little.

I know that we have to keep our school policy and programme under review to ensure that our teaching reflects changing social morals, but I think we do a good job of preparing our pupils for the onslaught of puberty and for all of the pressures placed on them by the media and their peers.

So, when the finger of blame for social problems relating to inappropriate sexual activity in teenagers is pointed at a lack of education, I have been known to become quite animated.

Joan Fenton is headteacher of Dyce Primary in AberdeenComment to scotlandplus@tes.co.uk