Modern nurses must be at once agony aunt, clinical nurse and public health educator.
They are also over-stretched, spending so much time on immunisation and paperwork they have little left to give pupils advice on sexual and personal health.
Almost a century after the School Medical Service was founded, a study by the National Children's Bureau finds it has low visibility and that few teachers or pupils understand its role.
A survey of nearly 3,000 pupils at six schools in England found that most did not know who their school nurse was, how they could contact her or what she offered.
Only in one school, with a full-time nurse did most of the pupils (63 per cent of boys and 85 per cent of girls) know who she was.
The study, by Nicola Madge and Anita Franklin, says there are fewer than 3,000 school nurses in the UK. Many are only part-time and most are employed in term-time only. This is a small number to serve 8 million schoolchildren in England alone, the authors say.
Their report urges the creation of more full-time nurse posts to provide continuity outside term-times. It also wants nurses working in the community as well as at school.
More work is also needed to reach boys, who are less aware of the service than girls and reluctant to use it. While girls with problems liked to talk to somebody, boys preferred the anonymity of telephone helplines or the Internet.
The report, Change, Challenge and School Nursing, was launched at a London conference last Friday.
Full report from NCB Book Sales, pound;10.95 plus pound;3 pamp;p. Tel. 020 7843 6029 or buy at www.ncb.org.uk