More than 3,000 women a year are travelling from Ireland to England and Wales for an abortion, a committee has been told.
Last year 141 of the 3,000-plus terminations were cases where the foetus was at a substantial risk of significant disability, the Oireachtas committee debating the Eighth Amendment to the Constitution heard on Wednesday.
The committee was discussing termination in cases of foetal abnormality.
Dr Peter Thompson, a consultant in foetal medicine at Birmingham Women and Children's Hospital, warned the committee against making a list of foetal abnormalities that might be permitted grounds for an abortion.
He said that due to the ever changing progress in medicine, "conditions would need to be added and removed from the list on a regular basis".
Dr Thompson strongly advised the committee against "being prescriptive and using the term lethal abnormality".
"The problem is there is no agreed definition as to what lethal actually means," he said.
"Is it all foetuses with that condition die before birth, that they die either before birth or in the neonatal period despite supportive therapy, a baby that usually dies in one of these two periods of time or is it that it has been noted that there is an association between the condition and death?" he asked.
Dr Thompson added that counselling women whose pregnancy is complicated by a foetus with a severe abnormality "is not a binary state of affairs but rather a complex discussion that requires a description of risk and probability".
Eamonn Moran, principal officer in the Curriculum and Assessment Policy Unit in the Department of Education and Skills, told the committee that access to sexual and health education is an important right for students.
"Schools have a responsibility to provide for this, in consultation with parents, having regard to the ethos of the school.
"Social, Personal and Health Education (SPHE) is a mandatory curriculum subject in all primary schools and in post-primary junior cycle," said Mr Moran.
He added that Relationships and Sexuality Education (RSE) is required at all levels, from primary through to senior cycle, and that the department has set out the content for each of these programmes in SPHE syllabuses and guidelines.