Their programme has been modified over the past five years to integrate sex education within a broad health curriculum covering such topics as personal hygiene, diet, smoking and drug and alcohol abuse. It is also firmly grounded in the teachings of the Catholic Church and tackled at a pastoral as well as educational level.
The British Medical Association and, more recently, Professor Michael Adler from University College London Medical School's department of sexually-transmitted diseases, have produced reports stating that improving sex education is one of the most immediate ways of raising standards of sexual health. Professor Adler's report also says there is no evidence that sex education encourages children to become sexually active at an earlier age.
But many teachers are in a quandary. While the 1993 Education Act makes sex education a compulsory part of the national curriculum, it also allows parents to withdraw children from lessons on HIV or AIDS, sexually-transmitted diseases or sexual behaviour. Teachers in Catholic schools are in a particularly invidious position, equally wary of parents' reactions and of contravening the teachings of the Church.
But as monks, priests and teachers equipped with clinical training, Father Christian Shore and Father Cuthbert Madden believe they have the confidence and knowledge to take a radically forthright approach - and that they have the backing of parents to do so.
Father Cuthbert, who used to practise as a physician, says, "I've worked in STD clinics, in obstetrics and gynaecology. I've also worked in the field of infertility. All aspects of sexuality were part and parcel of my job. Boys are more likely to be embarrassed than I am. It's just one more bit of life that needs to be talked about. We don't deal with it as a separate subject because that gets it out of proportion. But we do want boys to be informed.
"You can't teach about sex and sexuality without giving advice on contraception, and anyway boys ask about it. They know what the Church says, but they can make up their own minds based on knowledge rather than peer pressure or fear. They ought to exercise their own choices."
Professor Adler highlights the worryingly high incidence of sexually-transmitted disease among teenagers. Father Cuthbert agrees that ignorance must be dispelled. At Ampleforth boys are told what happens at an
STD clinic. "You wouldn't believe the myths about sexually-transmitted disease," he says, "like the one that you have wire brushes thrust down your urethra. It is important they understand the long-term and the short-term consequences of sexually-transmitted disease. So they are informed that genital warts are one of the causal factors of penile and cervical cancer and that chlamydial infections are one of the causes of infertility."
Father Christian, who entered the monastery halfway through his training to be a dentist, is housemaster and head of biology. He says: "As a medical student I worked in casualty at London's King's College Hospital. In Camberwell in the middle of the night you see life. We are confident of producing a well-informed health education programme, but not from a morally neutral standpoint. Our teaching is firmly rooted in the Christian,Catholic context. Parents are also happy that their children are getting such upfront health education. We have had not one complaint."
Homosexuality is dealt with openly in the sixth form. Father Christian says: "Some boys will be coming to terms with their homosexuality. Most gay men will have some idea by that stage. I emphasise that boys should seek advice and not treat it as a disease. I ask them to think about the language they use in relation to homosexuality in the certainty that sometime they will live or work with somebody who is gay.
"While we stress that the proper place for sex and genital relations is within marriage, we also stress that there is no place in the Catholic Church for homophobia, which leads to victimisation.
"We teach that sex is a powerful force in one's life and if not handled properly it can destroy us. Nobody goes through life without a problem with their sexuality. Everybody needs to seek advice at some stage. We try to give pupils the confidence to do that."
In Sussex, Sister Brendan Ryan, director of religious education in the diocese of Arundel and Brighton, has also taken matters into her own hands.In the absence of any national guidelines she has supervised a draft consultation document, Education in Personal Relationships in Catholic Schools, due to be published soon. She has already received enquiries from interested teachers from all over the UK.
On the basis that children should be innocent but not ignorant, the document outlines a curriculum for dealing with the areas of self, family and community at all key stages. Sex is not dealt with as a separate issue to the life "of the whole person" although it is dealt with directly.At key stage 4 on self and sexuality, for example, the document says pupils should "develop positive attitudes towards their own sexuality, know what is meant by responsible sexual behaviour, know what is meant by sexually-transmitted diseases", and so on.
Contraception, HIVAIDS, the safe sex argument and use of condoms are all included. Sister Brendan says: "We look at the whole person. We have to teach children from where they are. We teach from the Catechism of the Catholic Church but we have to arrive at a personal education that is open.We are not about making judgments on people's lives."
Sister Brendan, an inspector for the Office for Standards in Education, is also a member of the National Board of Religious Inspectors and Advisers and was formerly head of a primary school. Part of her vocation has been to work with socially disadvantaged children, and she is used to dealing with questions head-on. She says: "When children ask you direct questions you cannot say 'I can't answer you' - that is not educational. I usually say 'What do you want to know and why and what do you know already?'"
Some Catholic schools are using this programme already and Sister Brendan presents the diocesan perspective to parents. She says: "I encounter no hostility. Many parents realise they need support. This programme can give teachers the confidence to build secure partnerships with parents."