A study published today says the education level of the mother is particularly important in giving a child a good start in life.
Well-being includes the child's reading and mathematical ability, their social and emotional adjustment as well as their physical health.
Family Relationships And Family Well-Being: A Study Of Families Of Nine-Year-Olds In Ireland, was compiled by researchers in UCD and published today by Children's Minister Frances Fitzgerald.
Based on a sample of just over 8,500 nine-year-olds, the findings provide a revealing insight into modern-day Irish families.
"It shows family type is not the overriding influence on the well-being of a child," said lead author Dr Tony Fahey, of the UCD School of Applied Social Science.
"The single most important mechanism that public policy can use to combat family problems is to tackle educational disadvantage," he added.
Children whose mothers only have a primary education are almost five times more likely to have low reading and maths scores than children of mothers with a postgraduate education.
Eight out of 10 of nine-year-olds in Ireland live with both their natural parents while 17.5pc are in lone parent families.
Some 3pc are in step-families which, in nearly all cases, is when the mother has found a new partner. Better educated parents were shown to be more likely to delay having children until their late 20s, while the least educated mothers were more inclined to have a first child before 25.
Mothers with little or no secondary school education were found to be five to six times more likely to smoke. And they were more than three times more likely to show depressive symptoms than mothers with a postgraduate education.