The Redemptorist magazine, Reality, has said the onus is on parents, rather than schools, to ensure children are well informed and fully understand what having sex means.
The comment, by the magazine's editor Father Gerard Moloney, follows publication of details from guidelines being prepared by the Catholic bishops' catechetics commission which say that in relationships and sexuality education priority should be given to the role of parents. The guidelines will be circulated to school boards of management throughout the country, towards the end of next week.
The Department of Education's Relationships and Sexuality Education (RSE) programme becomes part of the curriculum in primary schools from next month.
Father Moloney's editorial calls on parents to talk "frankly and openly" to their children about sex and "make a stand regarding what is sexually right and wrong.
"Parents must explain the sound religious and moral reasons behind [their] beliefs. Adolescents need a clear set of standards to compare with the values they are getting from our sex-obsessed world."
Parents are warned that teenagers are under "severe pressure" to have sex. Father Moloney says a "tragic result" of present-day attitudes to sexual activity was that children who are not having sex think there is something wrong with them.
The editorial concludes that, although attitudes to sex are less negative today than they were in the Ireland of 40 years ago, this is not necessarily any healthier for society.
Ronan Keating, lead singer of Boyzone, is featured on the front cover of the magazine, which quotes his description of virginity as "a very special thing" and his religious conviction that he should not sleep with anyone until he is ready to be a father.