A survey of sexual attitudes among Catholic schoolchildren has shown many of them disagree with the Church's official teaching.
The survey of almost 800 pupils in Northern Ireland was carried out by the Catholic Church's marriage care service, Accord.
Fifteen and 16-year-old pupils in 12 Catholic secondary and grammar schools were asked a range of questions about sexual relationships and the way they are taught about them at home and at school.
The research showed almost 30% of 15 and 16-year-olds had had sexual relations and few of them agreed with the Church's rulings on sex before marriage.
The same proportion believed there was no need to marry before having children.
Only 18% believed that sex outside marriage was wrong.
The research also showed that most pupils prayed, respected their parents and believed a happy marriage was very important.
It also said that sexuality seemed to be a taboo subject in the home with parents reluctant to talk about it.
The pupils said they would rather discuss it with a school teacher with whom they got on well.
Accord said it was now preparing a training programme for parents and teachers on relationship education and teaching young people how to make informed choice.