Secularist organisation Atheist Ireland has called on the Department of Education to ensure that second-level students are able to exercise their right to opt out of Religious Education should they wish to.
Atheist Ireland says it also wants to remind parents, over the summer months, of their legal right to have their child opted out of the subject.
The body has asked the department to issue instructions to schools to ensure that Religious Education is timetabled in such a way as to give students real choice.
The Constitution gives parents the right to withdraw their children from religious instruction. However the subject is timetabled as a core subject in all schools, just like English or Maths, with no alternative offered.
Atheist Ireland says Religious Education should be treated as other optional subjects such as Home Economics or Accounting are; and timetabled in a way that provides students with real options.
Last year there was controversy when a State-run school in Limerick initially refused to allow a First Year student to opt out of the subject.
The then minister for education Jan O'Sullivan confirmed that students or their parents had a legal right to do so.
Publishing a study of the Religious Education curriculum, Atheist Ireland said if children were being left "stuck at the back of the class" then that was discrimination.
Atheist Ireland's Jane Donnelly said the RE curriculum itself also discriminated against non-religious children.
She said documents received by the organisation in a Freedom of Information request showed that while the country's Catholic and other main Christian churches had a significant input into the design of the programme, no other religious or non-religious organisations had been invited or allowed to participate, despite requests from several of those organisations.
Speaking at today's launch, parent John McKenna said his son was due to begin second-level at a State-run or Education and Training Board (ETB) school in Dublin this September.
He said he and his wife had been told that if their child wanted to opt out of Religious Education then he too would have to remain at the back of the classroom, and that he would not have the option of studying another subject during this time.
All ETB schools are obliged to teach religion. This was a stipulation that the Catholic church made to the State during the development of the State-run school system.