Just how much do children know and how much should you tell them?
The balance in teaching about sex is a fine one. It is easy to come unstuck; witness the controversy over Mars Bar parties and adulterous affairs being discussed in class. But at Whitecote primary in Bramley, Leeds, headteacher Paul Wagstaff believes he has the balance right.
"There's a very thin line between success and disaster in this area," he said. "But we have always felt that the primary school, with its close family atmosphere and the genuine trusting relationships children have with their teachers, is the natural place to begin the process of sex education."
His attitude has proved right. Whitecote beat schools from across the country to take the Fawcett Society's "Positive Action" award for its work on sex education. This prize is awarded by the society, a national campaigning association for equality between the sexes, for equal opportunities in education.
The 440-pupil school began planning its current policy two years ago with the abolition in Leeds of the middle-school system where sex education had traditionally been taught. There was widespread discussion between staff and parents before the programme was introduced and lessons started in September, 1993.
Sex education is taught by teachers and thoroughly integrated into the curriculum. "We don't have strangers coming in, talking for an hour and then disappearing. The children are being taught by people they know and trust in a secure environment," said Mr Wagstaff. "Nor is it a question of one sex education lesson, in isolation, each week. It is incorporated naturally into the timetable."
Formal sex education begins in Year 4 with sessions on "My Body as a Machine" which look not only at the digestive and respiratory systems but the reproductive system too.
In Year 5, sessions on "Images" are introduced with children being encouraged to think about their own image as they approach puberty; and in Year 6, sex education is incorporated into topics dealing with development - how countries develop; how children develop into adults; and how babies develop.
Some sessions are mixed, others single-gender groups, but throughout, the children are encouraged to ask questions and discuss what they have learned, either during the session or privately afterwards.
Karen Wright, the school's health education co-ordinator who led the programme development, said there had been some apprehension about how the children would respond. "I must admit we were expecting giggles," she said. "But there just weren't any. The children accepted it all quite naturally."
Some children had no prior sex education; some had been told a little by their parents; and some knew a surprising amount.
"A lot of sex-related issues are dealt with in television programmes such as Neighbours and EastEnders which children watch," said Mrs Wright. "So a number had picked up a certain amount already."
Far from being embarrassed, the children were eager to learn. "They had heard scare stories from older brothers and sisters or picked up bits from friends and were confused about certain aspects," said Mrs Wright. "Some girls, for instance, thought that when you started your periods you bleed every day for the rest of your life."
HIV, Aids and contraception are subjects left for secondary school. "There are some areas that don't affect them at the moment," said Mrs Wright. "We see our sex education as the beginning of a process that will be developed as the children get older. If a child asks whether every time you have sex you are going to have a baby, we tell them 'no' but the full answer to that will come later when they start learning about contraception."
For the teachers it was the first time they had taught sex education. "There were some initial fears that children would ask: 'Do you do it?' and they would feel embarrassed," said Mrs Wright. "However the success of our approach is reflected in the sensible way the majority of the children behaved."
Parents too were relieved and pleased that the job of helping their children to discover and come to terms with their sexuality was to be shared. "Many expressed the view that the sex education programme would be a valuable way to help them start talking to their child about this sensitive and, some would say, embarrassing subject," said Mrs Wright.
Karen Johnson, whose son Ashley, 11, is a pupil at Whitecote, admitted many parents were nervous talking to their children about sex. "This way helps to break the ice," she said.
Catherine Broadhead's daughter Samantha, 10, took the subject in her stride. "She felt comfortable and was quite happy to talk to her teachers and to me," she said. She has no fears for her eight-year-old son, Jonathan, about to embark on sex education. "The school has developed the programme well. The children will do Vikings one day - and sex education the next. It's all very natural."
In making the award, the Fawcett Society decided that the traditional primary structure, where class teachers knew their pupils well, was highly appropriate for sex education work, and keeping the teaching in the hands of class teachers had been very successful.
The judges were also impressed by the team approach established in the school, involving governors and parents both in the consultation period and once sex education had been introduced. This involvement had been fundamental and essential to the whole project, they thought.
They also applauded the monitoring used to assess pupils' understanding, and the fact that one-to-one sessions were available if a pupil had not understood or missed a lesson.