There is no denying that dual standards exist widely in Irish society. It is sheer hypocrisy to pretend otherwise. If schools adopt a "head in the sand" attitude and ignore these double standards or attempt to deny they exist when deciding on the curriculum for relationships and sexuality programmes, they will be failing children.

It is incontestable that the parents of a significant number of children - and indeed a number of teachers - give lip-service to one standard of sexual morality while in private they live by different standards. These double standards create problems for religion teachers, school chaplains and teachers dealing with relationship and sexuality education.

The parents of one in four children entering primary school are not married. One result of this is that teachers have to be careful when they are talking about "the family". They cannot assume that every child in a class has two parents who live with them.

The difficulty of finding an inclusive language to talk about the many different family situations that are now commonplace is a problem that must first be acknowledged before a solution can be agreed.

Children learn their values, or lack of values, from parents, who are their primary educators. It is widely known that not all the parents of children who attend Catholic schools accept or live by church teaching. Many couples whose marriages break down separate and some go on to find happiness with a different partner.

An increasing number of single mothers think that the father of their child is irresponsible and plan to remain as lone parents. The Department of Education has made provision for a consultation process which involves parents and is in line with the core values and ethos of a school. This ethos is created by all the pupils, parents (regardless of their marital situation), teachers and management. It includes those who accept church teaching and those who don't. Most Catholic couples of childbearing years are using contraception. Teenage students know their parents do so in defiance of church teaching; many see no reason why they shouldn't do the same.

The teaching authority of the Catholic Church has been greatly eroded, not so much by the recent sexual scandals but by the Vatican's insistence that contraception is intrinsically evil.

When parents ignore or defy church teaching about sexual behaviour, it is not surprising that teenagers also do so. Adolescents are more powerfully influenced by what their parents believe than by what is taught in school. More and more I am meeting teenage girls whose mothers have them on the three-month contraceptive injection. Parents are happy to stand up at school meetings and say they check their teenager has condoms going out at the weekend.

Why can't we be honest and admit that one reason that religion is having less and less effect on the sexual behaviour of young people is that it was not virtue but the fear of an unmarried pregnancy that encouraged previous generations to save sex for marriage?

Sexual behaviour changed almost overnight once contraception became generally available, and that fear went.

Behaviour that is controlled by fear will change as soon as the fear goes.

We now live in a pluralist society. A large number of parents are so fearful of an unwanted pregnancy that they want teenagers taught about contraception. This creates a dilemma for teachers, because there may be other parents who are opposed to such information being given.

I tell teenagers that any sexual activity that creates distance between two people or that leaves either of them feeling used, upset, ashamed, guilty or resentful is bad for them. They readily agree that this is true for every behaviour from snogging to having sex. Many have already learned painful lessons from personal experiences. They are surprised when I explain that this is the teaching of the Christian churches.

I suspect that most other parents would agree with moral theologian Vincent J Genovesi. He says: "Young people are crying out for a sexual morality that makes sense in terms of personal relationships - chastity is honesty in sex." They will not find it if their teachers fail to acknowledge the double standards that create confusion about moral values.