Teenagers it seems will go to extraordinary lengths to avoid being teased.

Let me tell you the story of four children who belong to three families - all friends with each other. I shall call the children Susan Smith (14), Jane Jones (14), John Brown (13) and Fred Brown (11). All four attend - or will from September when Fred joins the others - the same school.

We start with Jane and John who are friends from infancy: they enjoy the same sports and have generally similar tastes and interests. As you will have noticed one is a girl and the other is a boy. When John started going to the same school as Jane, in order to avoid teasing about being boy and girl friend they casually let it be known that they were half brother and sister. (They aren't.)

In the meantime Susan, who shares the same sporting interests as the others, lives next door to Jane, and whose father many years before either was married was briefly Mrs. Brown's boyfriend and is also Jane's brother's (the real one) godfather, has for John's sake became cousin to both Jane and John although she and Jane could simply have been friends without comment. However, Fred has complicated the issue by telling some people that he and Susan are half brother and sister.

I do hope that Social Services never get hold of this story, especially if - as seems quite likely - the boyfriend/girlfriend scenario does eventually overtake the 'simply friends' situation with John and Jane, or possibly John and Susan.

Back on Planet Grown-Up the assorted parents are wondering just who had an affair with whom to produce all these tangled relationships.