A survey of 200 second-level pupils found that a quarter of respondents said they received relationships and sexuality education last year.
Minister Barry Andrews said he is concerned about the finding. However, the survey contradicts other work which says 
that there are high levels of participation in RSE programmes.
However, it also found that the vast majority of respondents said they had received Social Personal and Health Education.
The 200 teenagers were from 94 schools throughout the country, or on average two a school. Some of those surveyed said they had received sex education within religion class.
Respondents said teachers were sometimes embarrassed to talk about sex, in some cases for religious reasons.
The survey was carried out by the Dail na nOg council and took place at Dail na nOg meetings. It is extremely unlikely that the survey was nationally representative as the sample was not randomly selected.