The Irish Family Planning Association has told politicians that it is "deeply concerned" at the public health impact of "inadequate, inconsistent, and poor quality sexuality education" in many schools in Ireland.
The IFPA was among a number of agencies and academics to address the Oireachtas Committee on Education today on the issue of Relationships and Sexuality Education in schools.
The committee is holding hearings as part of a review of the existing RSE curriculum in schools.
The review is also examining how the curriculum is delivered, and by whom.
In its submission to the committee the IFPA said it sees the impact of "poor-quality sexuality education at first hand every day" in its pregnancy counselling centres and in its clinics.
It said there is an "immediate" need to develop a high quality comprehensive sexuality education programme promoting accurate and age appropriate knowledge, attitudes, and skills, particularly in relation to contraceptive use, sexually transmitted infections, abortion, sexual orientation, pornography, consent, and gender equality.
The Rape Crisis Network, in its submission, also recommends a comprehensive review of programmes, and says the matter is "urgent".
The RCNI said the State has been historically "resistant and ambiguous towards sexual autonomy and liberation" and blames this for what it says are the "silences, paralysis and gaps" found in sex education in schools here.
The RCNI called for clarity and joined-up thinking and points out that there are currently at least four different government departments, and at least six strategies with a role in shaping health education.
Youth development organisation, Foróige, told members of the committee that the continuous feedback that it gets from young people is that sex education in schools is either non-existent or, where it does exist, too narrowly focused on the biology of sex.
Foróige said research finds that young people would welcome more education about sex and relationships.
In its submission Atheist Ireland said the results of the recent referendum show that legislators can no longer assume that even most Catholic parents want Catholic sex education for their children.
The organisation said that Ireland needs to move towards a secular, human rights based school system that treats everybody equally.
The committee also heard from a number of academics who specialise in the area of sexual education.
Dr Aoife Neary of the University of Limerick told politicians that uncertainties around religious ethos continue to constrain the delivery of Relationships and Sexuality Education in Irish schools.
She said there is an urgent need for clarity on how religious run primary and post-primary schools can meet the RSE needs of all children equally.
Dr Neary said the current curriculum, which was written 20 years ago, does not adequately reflect the realities of children and young people's lives.
She added that young people are already engaging with the area in their own everyday lives, and that the significant challenge now for the system is to catch up with them.