Supportive relationships between parents and children are vital for preventing problems such as heart disease and drug addiction in later life, the Health Committee was told, on 7 November 2012.
Representatives from the Republic's Health Service Executive (HSE), which is responsible for providing health and personal social services, gave a briefing to the committee.
Its representative, Conor Owens, spoke on the Triple P - positive parenting program.
It was rolled out free in 2010 to all parents living in counties Longford and Westmeath who had children aged seven years and under.
The programme involved courses, seminars, group sessions and website tips.
Mr Owens said the project aimed to enhance parenting skills in the hope of preventing behavioural, emotional and developmental problems in children.
He explained that children were affected by their environment, their neighbourhoods, and how they were parented.
"The home environment actually alters the biology, so if parenting is aggressive or there are significant problems around violence or inconsistencies in the home, that will actually change the structure of an infant or a young child's brain," he said.
"What adverse childhood experience does is expose a child to toxic stress, which alters the development of the brain and increases the likelihood of engaging in risky types of behaviour and so leading to depression, heart disease and drug addiction."
The evidence session was called following a decision by the committee to undertake a short review to identify effective interventions to address health inequalities.
This stemmed from an earlier committee evidence session with the Public Health Agency which revealed that although the general health of the population had been improving, the rate was not equal across the population.
The second part of the debate can be viewed