Ireland’s welfare system may encourage lone parenthood because it penalises single people who marry or cohabit, a new study has suggested.

The study, published yesterday by the Economic and Social Research Institute, found that Ireland has an unusually high level of never-married and previously married single parent families by comparision with other countries.

The report used data from the 2006 Census, and found that 9.4pc of families with children are headed by never-married lone mothers, while an additional 12.3pc of such families are headed by previously married lone mothers.

Under the Irish welfare system, if two single people on welfare marry or cohabit, they stand to lose a total of around €65 per week between them. This is sometimes called the ‘marriage penalty’ by social policy experts.

The authors note that “[t]here has been some concern in recent years, for example, that welfare supports for lone parents, of which the One Parent Family Payment is the centrepiece, may have a disincentive effect on partnership and may give rise to a higher incidence of lone parenthood than would arise with a more couple?friendly system of family income support”.

They also point out that the figures illustrate “a greater tendency for women who become pregnant outside of marriage to go it alone and not cohabit with or marry the father of the child”.

They write: “It is in this connection that the possible disincentive effects on partnership of income supports for lone parents come into play, as mentioned at the outset of this chapter.

“Welfare payments to lone parents are conditional on their partnership status, so financial disincentives not to form or to conceal partnerships do exist.”

Meanwhile, the study notes that Ireland has a lower rate of second marriages and step-families compared to other countries. Only 2.3pc of families with children are headed by married parents who have previously been in other marriages.

According to the study, 75pc of Irish children live with two married parents, 18pc with a lone parent and six percent with cohabiting parents.

In terms of cohabiting couples, the vast majority, 76.8pc are made up of never-married couples, while 11pc of cohabiting couples were comprised of a formerly married man and a never-married woman, and seven percent were comprised of a never-married man and a formerly married woman.

The study showed that 8.4pc of cohabiting couples were made of two previously married people.

The survey also showed that the more religious a couple were, the less likely they were to have cohabited and that the chances of a child living with both married parents were much higher where the parents have higher levels of educational attainment.

A couple in their 30s who both have third-level qualifications are less than half as likely to cohabit as a couple who both have lower second-level qualifications, the study shows.

In comparative terms, Ireland ranks alongside countries like the Czech Republic (19pc), Germany (18pc), Poland (17pc) and Hungary (17pc) in terms of children under 14 living with lone parents.

Countries like the UK (31pc), Latvia (32pc) and Estonia (30pc) have the highest rates of children being raised by single parents, while Finland (5pc), Greece (6pc) and Italy (8pc) have amongst the lowest rates.