SEX education in Scottish schools is "inadequate", raising fears that the soaring rates of teenage pregnancy and sexually transmitted disease are going unchecked.
An official report has criticised the quality of lessons in secondary schools because of lack of staff training and knowledge about which topics to teach children.
In some schools teaching is so poor that experts believe it is undermining the sex
education curriculum and failing to teach pupils the skills they need to have healthy relationships.
Last night, critics called for urgent improvements to tackle the nation's high rates of disease and teenage pregnancy, which are among the highest in the western world.
Three years after its launch, there are now questions about whether a £15m sexual health strategy is working.
But teachers say they are limited in what they can do because of fears over parents' objections that lessons are too explicit.
The research was carried out for the Scottish Government's health promotions agency, NHS Health Scotland, by Dr Edwin van Teijlingen from the department of public health at Aberdeen University. He examined hundreds of schools and interviewed key professionals with a knowledge of schools across the country.
Schools are free to choose their own sex education materials and programmes. Some use programmes devised by experts and others make the lessons up 'in house'. But the report, A Review of Sex and Relationships Education in Scottish Secondary Schools, found:
• Doubts about the "consistency and quality" of sex education because of "inadequate training of staff"
• Many schools uncertain which topics to include in sex education
• Schools failing to deal "competently" with gay, bisexual or transgender issues
• Many schools failing to consult outside experts such as school nurses
• Other schools "parachuting" in sexual health workers who have no knowledge of the pupils
• Concerns about the "dominant moral code" offered by Catholic schools.
Van Teijlingen said: "Most schools are only doing a half decent job in sex education.
"Schools do different things because they have great freedom, but they fill the sex education curriculum with whatever is available in their areas, and some areas don't have things available – 14% of teachers had objections to the lessons and we believe this is because they were not comfortable with them.
"We have doubts about the consistency and quality of the programmes as a result.
"Schools have lots of different things to do, and sex education is not their first priority, but we have problems in Scotland like teenage pregnancy so we need to do something about it."
Catholic schools, he added, were failing to address fully the issue of homosexuality. "They were uncomfortable about issues such as homosexuality, which means pupils are less likely to go to teachers. They parcelled sex education alongside marriage rather than sexual health and we think that will create problems for some pupils.
"They should also signpost pupils to family planning clinics or support groups for young gay people. Even if they don't agree with it they should let young people know these services are available."
Van Teijlingen has produced a raft of recommendations which have been sent to Public Health Minister Shona Robison. They include better support and more guidelines for schools and better teacher training.
But many teachers say the main problem is a fear over parents' objections.
Alan McKenzie, of the Scottish Secondary Teachers' Association, said: "To be candid, this is a sensitive area, particularly around issues such as homosexual relationships, and a lot of parents' views are fairly controversial. There is a reluctance to deliver sex education because of sensitivities and there is a degree of nervousness about parents' views.
"We have to be very sensitive to the wishes of parents. We have to tread warily."
The revelations will be alarming to the Scottish Government as it tries to reduce high rates of sexual disease and teenage pregnancy. The latest figures show 56.7 pregnancies a year per 1,000 women under 20 in Scotland.
Diagnoses of sexually transmitted infections are on the rise among men and women. Last year there were 17,926 cases of chlamydia and 1,290 cases of herpes. The country's sexual health strategy called on schools to support "consistently high quality of education about sex and relationships".
But Eleanor Conor, of the Scottish Parent Teacher Council, said the failure of schools to teach pupils properly would lead to more sexual health problems for youngsters.
"Poor sex education causes problems for children and has an impact on sexually transmitted diseases and unwanted pregnancies," she said.
"Ignorance is awful and it leads to young people putting themselves in danger.
"There are some examples of good sex education programmes out there and they need to be expanded into other schools using ideas such as sexual health drop-in clinics and free condoms."
A spokesman for the teaching union the Educational Institute of Scotland described sex education as "challenging".
He said: "Providing appropriate sex and relationship education, with due consideration to the age of pupils and the wishes of parents, is always an important and challenging issue for schools. Improved resources, including support for teachers both during their initial teacher education and also as part of their continuing professional development, is key to improving the provision available across the country."
A Catholic Church spokesman said the education programme used in their schools taught that homosexuality was intrinsic to the individual and homosexuals could not be discriminated against. "However, we do not condone homosexual behaviour and we would not send pupils to family planning clinics, abortion providers or other agencies."
Facts of life• 14% of Scots teachers have 'objections' to sex education lessons.
• Scottish rates of STDs and teenage pregnancy are among the highest in the West. There are 56.7 pregnancies a year per 1,000 women under 20.
• 2007 saw 17,926 cases of chlamydia and 1,290 new cases of herpes.
An 'embarrassing and unnecessary' lessonWHEN Sarah Robertson turned up for her sex education lesson earlier this year she and her schoolmates had a class they are unlikely to forget. Instead of a chat about the birds and the bees, her teacher produced a plastic model of an erect penis and handed out condoms to the 15-year-olds. First they were shown how to put the condoms on the model, then they had to perform the task themselves.
This kind of lesson, at a school in Edinburgh, is standard in many secondaries but Sarah and her fourth-year classmates found it not only embarrassing, but unnecessary. "Putting a condom on is not rocket science," she said. "I just don't think we needed to do that. The whole class was mortified and in hysterics."
An earlier lesson, which required the pupils to write down slang terms for sexual acts, proved equally riotous. "One boy just made words up for a joke, and the teacher didn't realise and was reading them out and asking us what they meant. I also felt that lesson was not particularly educational."
But if plastic penises are at one end of the spectrum in sex education, the content of lessons in Catholic and some rural schools is at the other. There, the prevailing ethos is that everyone will go on to get married and have families.
In a report commissioned for the Scottish Government, Dr Edwin van Teijlingen, from the Department of Public Health at Aberdeen University, concluded that he had "doubts" about the "consistency and quality of sex and relationship education programmes, as a result of inadequate training of staff and uncertainty about which topics should be included".
The quality of lessons across Scotland is patchy, he found. 14% of teachers were unhappy at delivering the subject and many schools did not make good use of outside expertise such as school nurses or family planning doctors.
