Researchers at Bristol University’s Institute of Child Health and the Schools Health Education Unit in Exeter have finally confirmed what everybody in primary schools has suspected for a long time: that children are entering puberty earlier than ever. They have found that at age eight, one girl in six experiences the onset of puberty; for boys, it’s one in 14. A generation ago, the average age for girls to start their periods was 13 and six months. Now, it’s 12 and 10 months.

This doesn’t mean that Year 4 classes are suddenly going to be teeming with menstruating girls and boys with breaking voices and razor cuts. For both sexes, the onset of puberty is the beginning of a gradual process. In girls, it takes about 18 months from the first signs of breast buds, followed a few months later by the start of pubic hair, until periods start. In boys, early signs are pubic and facial hair and their voice breaking.

Why children are developing earlier is a matter of conjecture at this point because there’s no hard evidence to explain the phenomenon. Various theories are being suggested. The increase in body weight caused by a combination of better nutrition and more sedentary lifestyle could offer a clue. So, too, could environmental factors like oestrogens in food or stress from, for instance, divorce in the family.

Whatever the reasons, there are clearly implications for primary schools. One of the researchers on the Schools Health Education Unit study, which surveyed 9,000 children, is concerned that schools aren’t introducing sex education early enough. Dr David Regis says: “Some of the children who took part in our study said they weren’t doing sex education even in Year 5. Clearly, there are schools where any discussion on these issues is being kept until the last minute, in Year 6.”

John Coleman, director of the Trust for the Study of Adolescence, adds:

“Even in good schools, teachers are very anxious about teaching younger children the facts of physical development. If eight-year-olds, even small numbers of them, are showing signs of puberty, schools should be thinking of introducing health education programmes in Year 3 or 4.”

Primary schools also need to address the issue practically. Bins with lids should be installed in girls’ toilets and emptied regularly. In addition, schools need to think about the arrangements for changing clothes for PE. If even one girl in a class is maturing early, it’s worth avoiding her embarrassment by having the girls and boys changing in different halls or rooms.

Bringing parents on board as partners is another way John Coleman believes that schools can help children who are moving early into puberty. “Schools have a key role to play in educating parents about physical development. Parents will be worried when they see their children developing early, so why not have parents’ evenings around these issues, with information and discussion linked to general health education - rather than pigeon-holing it as sex education?” A crucial thing, says Jane Lees, co-author of Passport: A Framework for Personal and Social Development, is that schools develop their own schemes. Her book, which has been distributed free to every school in the country by the Gulbenkian Foundation, “is there to back up what the best schools are already doing”. It gives step-by-step guidelines on personal and social development at each key stage, amplifying the national curriculum frameworks for PSHE and citizenship in a way that enables teachers to integrate different initiatives within a single programme.

One school that Jane Lees hs been working with as part of the Healthy Schools Project in Wandsworth, south London, is Trinity St Mary’s C of E primary. There, PSHE co-ordinator Sue Haslam introduces a programme in the nursery, starting with naming parts of the body. It moves on through the infants to look at chickens laying eggs, dogs having puppies and, later, at key stage 2, at how babies are conceived and develop. In Year 4, teachers talk about the genitals and in Year 5 about periods. By Year 6, when half the girls are already menstruating, the focus is on emotions, peer pressure and relationships.

Why only cover periods in Year 5? One reason is that some children are still only nine until the July or August after Year 5, “and may not be able to cope with the information,” says Sue. “But if we had a particularly mature group of Year 4 girls, we might do it earlier. There are no hard and fast rules. This year half the girls in Year 6 were menstruating, but generally, it’s about one third. You have to play it by ear, being alert to where the girls are in their development.”

An overriding consideration in how to pitch the subject of puberty for any class, no matter what its composition, is communicating that every person is different. “One thing I want to avoid at all costs is children feeling they’re not normal,” she says. “That means making it clear that not everybody starts at eight or 11. We have to stop girls feeling ashamed of starting.”

She makes a point of suffusing the discussion of periods with a positive tone. “We talk about how in some cultures it is a cause of celebration.” This session is for girls only, giving practical information on how to manage menstruation as well as putting it into a social and cultural context. Both boys and girls learn about the mechanics of why periods happen, the possible effects on girls’ moods and how it relates to changes in boys’ bodies. “If you treat it as a normal part of growing up, I find that the children can talk about everything and feel comfortable asking about things that are bothering them.”

According to Jane Lees, the gender of the teacher shouldn’t be a barrier. “Some male teachers have done good work in this area in mixed schools.” At Trinity St Mary’s, a Year 6 teacher with children of his own is entirely relaxed about dealing with the issue. On the way to a school journey, one girl told him she was worried about getting her period while they were away. “Don’t worry,” he told her. “We’ve got lots of supplies.”

USEFUL TIPS

* Tailor a programme of personal, social and health education to meet the individual needs of your pupils, following the new national curriculum framework.

* Be attuned to children’s behaviour and physical development for early signs of puberty.

* Even if there’s only one child in a class who’s entering puberty early, it needs to be addressed, if not in a lesson, then by the class teacher or school nurse.

* Schools should devise procedures for when girls get their periods while at school (for example, where to go for supplies) and all staff be made aware of them.

* Girls’ toilets should be equipped with a bin with a lid for disposing of pads, which should be regularly emptied.

* There are no hard and fast rules or theories on single sex sessions being preferable to mixed groups. If pupils express a desire for them, they should be listened to.

* There should be the opportunity for children to discuss issues around puberty in small groups.

* It’s important that children feel comfortable asking questions. It can be helpful to have a question box if they’re embarrassed; answers should be given in class.

* Diagrams can be very useful in discussing reproductive organs and body changes.