Schools have a responsibility to be balanced in the relationships and sexuality education they offer pupils, Education Minister Richard Bruton said.
He was commenting on a row at a secondary school in Tralee, Co Kerry, earlier this week over a talk by the anti-abortion group LifeWorks to sixth-year students.
LifeWorks, which has the same Dublin address as the pro-life campaign, provides speakers to second-level schools across Ireland.
According to its website, its "multimedia rich presentations encourage classroom discussion on the value of life and the dignity of every person".
Some students at Mounthawk Secondary School stayed at home on Wednesday in protest at the talk.
According to reports, the school said it notified parents in writing in advance via students, but some parents complained they had not been notified directly and were not told of the nature of the talk.
The minister noted many schools used outside external providers as resources for their RSE programme. But he said "this may not be the best approach" and it was one of the issues that was being looked at in the review of sex education now under way.
Guidelines governing the use of external providers are expected as part of changes introduced following the review. It is also being looked at in the context of work being undertaken by the Department of Education in the area of the new student wellbeing programme and the use of external advisers for that.
Mr Bruton said he did not know the background to the Tralee case and did not want to comment on the specifics, but he said schools must understand their obligations.
The minister said it was an issue where schools must ensure they consulted with parents and were conscious of parents within their community having different views.
"In all cases, a school would want to be satisfied that the programme being pursued meets the expectations of parents and the curriculum.
"They have an obligation to ensure that. They have a responsibility to ensure balance."