Sex is all around us - and our children. The headlines scream ever louder: first the 12-year-old mother, then the 11-year-old father. Last week, the school gang-rape trial, in which a group of nine- and ten- year-old boys were acquitted of raping a nine-year-old girl in the school lavatories. Meanwhile, in the cinema, Nabokov's story of a paedophile's exploitation, Lolita, is still to be seen here, and its star, Jeremy Irons, is threatening to leave the country if the film fails to pass the censors.
So what do our children make of all this? Are we right - or is it even possible - to protect their shrinking childhoods for as long as we can, with a collective burying of heads? Or should we, together with their schools, take a bolder approach, and give them some straight talking about sex from a much younger age?
Children's questions should never be ducked, and it is not so unusual to find three- and four-year-olds with some pertinent thoughts about where babies come from. Anne Weyman, chief executive of the Family Planning Association, argues that all parents should begin sex education with their children well before the age of five.
"Children are naturally interested in their own bodies, and in their families, and we need to be much more positive about this. Often we don't introduce the subject of sex, but wait for them to bring it up; but this gives them the message that sex is different from other subjects, and that we don't think there's a need to talk about it."
Books can be a useful ice-breaker for the retiring parent of under-fives, such as Babette Cole's humorous Mummy Laid an Egg, and Claire Rayner's The Body Book. In a book such as the latter, a small child may well pay more attention to the section on food than to the one on reproduction, but the fact that it is there means that the child can return to it when interested, knowing it is not a hidden or taboo subject.
We worry unnecessarily about going into detail that children are not ready for when they ask a question, says Gill Lenderyou, senior development officer at the Sex Education Forum, a body funded by the Department for Education and Employment. "If they don't understand it, or are not ready for it, they don't remember it," she says.
Teachers in nursery schools can be usefully laying the foundations for "the fourth R" - relationships, as referred to by Estelle Morris, Under- Secretary of State for School Standards, herself a former personal and social education teacher. They can help children to make relationships with each other, to recognise and respect difference in others, and to begin to challenge stereotypes, says Anne Weyman.
Teachers are often fearful of drawing censure from parents and from the media, for introducing sexual material to children at an inappropriate age. But a well-thought-out sex education programme is essential if children are to make sense of the battery of sexual messages coming at them from the media and from friends, and not become thoroughly confused or incorrect in their notions.
"They need to be able to be critical of what's around them," says Carol Glover, headteacher of Sir James Barrie primary school in Wandsworth, south London.
For the past eight years, her school has run a full personal, social, moral and health education programme. Children become gradually more comfortable with talking about their bodies, and how the body changes; sex education begins formally at 10, covering sexual intercourse and contraception, as well as more contentious subjects such as Aids and homosexuality, if children choose to bring them up.
"This approach means that the children gain a natural understanding of these issues, rather than seeing them as something separate which shouldn't be discussed," says Ms Glover. "When children feel comfortable with themselves, can build relationships with others and feel happy at school through being open, they are able to learn better."
Gill Lenderyou, however, believes that sex education at 10 or 11 may be too late for some children - such as the growing number of girls who start their periods at nine.
"Ideally, you need to prepare children before they get to the next stage of their development. So you don't start talking about puberty at 11 or 12, but maybe at nine, and sexual activity at perhaps between nine and 11, as a preparation for secondary school."
Boys, almost inevitably, seem to fare worse in terms of their sex education than girls, receiving less help and information from their parents and their schools. Gill Lenderyou maintains, for instance, that schools should include both boys and girls in talks about menstruation, rather than sending the boys out, as so often happens - with the result that they can feel angry and cheated, fail to grasp the information, and retaliate by teasing the girls about it.
Obviously, teachers need to use discretion in determining which children may be ahead of others in their need for sexual information; getting children to form their own groups for discussion can be useful here, or setting up one-to-one talks with particular children.
Little and often is a key to providing sex education, rather than presenting it in a huge chunk, or hoping a BBC video will do the job for you. Also, for parents and teachers, it is important that this is a subject where you do not just tell children things, but draw them out and respond to their questions.
"In every survey of young people's view on sex education, what they say is, `too little, too late'," says Anne Weyman. "As adults, we have got to be a bit more open-minded about what young people want and need."
Facts of life in the UK
Primary schools are not required by law to teach sex education, other than the biological aspects of reproduction and the human life cycle as laid down in the science curriculum.
As a result, sex education is extremely patchy and variable.
Most schools lack the time, and the training, to build a coherent personal and social education programme, incorporating sex education, into their timetables.
Schools must keep parents fully informed of their sex education policy. Parents have the right to withdraw their children from any part of it that is not laid down by the national curriculum.
Surveys by the Sex Education Forum suggest that 95 per cent of parents want schools to teach sex education, and many hope their children will receive more than they did themselves.
Countries that devote more time to sex education than we do, and start it earlier, produce more young people who delay sexual activity, and make greater use of contraception. The Netherlands has the lowest rate of teenage pregnancy in Europe, followed by Sweden. Britain has the highest.Reuse content