Rapidly changing social and economic forces have punctured the notion of the Irish family as a single unit headed by two married parents, living under the one roof with their children. In the past decade, the orthodox nuclear family has gone from being the prevalent family structure to being one model among many.

In line with other Catholic states like Italy and France, the Republic is witnessing a fragmentation of its social landscape, with the sensitive area of families showing the starkest fissures. The most conservative estimates suggest that at least one in six families is now headed by one parent - that means there are up to 150,000 one-parent families in the Republic.

The RTE television documentary, States of Fear, gave us a glimpse of how official Ireland confronted this type of social development. The brutalisation of so-called "fallen women" was the concealed element of an official policy which sought to prevent any form of alternative social organisation.

While post-1945 statistics show there were between one and two thousand births outside marriage on average every year, as far as wider society was concerned these statistics were meaningless and the human stories behind them needed to remain shrouded in secrecy. Even the few individuals who addressed the issue only did so to re-enforce the connection between unmarried births and spiritual loss.

As Father Cecil Barrett, a close adviser of Archbishop John Charles McQuaid, put it in 1952, even material assistance to unmarried mothers would be "of no avail, unless the rents in the mother's spiritual fabric have been repaired".

The picture is sharply different now; one-parent families have, at least, a network of support groups and information centres to draw on. Recent figures from the Department of Social, Community and Family Affairs show that over 18 months, the number of people collecting one-parent family payments increased by about nine per cent. In other words, about 67,738 people were able to pass the Department's means test for the payment at the end of April compared to 58,960 at the start of 1998. While these figures are dramatic, they are only a partial snapshot of the overall increase in the number of one-parent families. Before attempting to examine the reasons behind this, it is important to note that one-parent families (as officially classified) can be unmarried mothers and fathers, separated people and widowed parents.

The increase in the overall figure comes from the enormous growth in the number of separated parents (see table) and unmarried single parents. While support services have been established (for female and, increasingly, lone male parents) and the climate has changed, the issue is still highly charged for politicians. A request for an interview with the Minister for Social, Community and Family Affairs, Dermot Ahern, by this reporter was turned down when officials were told it would be dealing solely with the issue of lone parents.

Even Dana Rosemary Scallon, newly-elected MEP and a firm believer in restoring the family to the centre of society, declined the opportunity to outline her views on the question of lone parents. Through a spokeswoman, she said she would need "a few weeks" to compose her views.

None of this is surprising in view of the public spat which took place during the 1997 election when Mary Harney faced a cascade of criticism after suggesting measures to encourage young single mothers to remain with their parents rather than establish one-parent homes.

"What is more compassionate: a system that forces young single mothers to isolate themselves in council houses, away from human contact and support, in order to receive benefits, or one which provides them with the option to live with the father or with their own family?" she said at the time. Lone parent groups countered by saying that young parents should not be made dependent on their parents and should be allowed to lead autonomous lives.

Since then many politicians have decided the issue of lone mothers and, in a wider sense, single-parent families, is off-limits.

THERE is no doubt the recent increases in the number of single parent families throws up a formidable dilemma; just to ask what implications the increasing figures have for society draws a range of responses. On the one hand Nora Bennis, the leader of the National Party, says the increases are the sign of a "de-stabilised" society. In terms of choice she claims single-parent units have little to offer women. "Women in the last few years, as the figures have been increasing, have been given a bum steer," she says.

She argues that liberals have sent out a message to women that having a baby on your own, separating or divorcing are options to be seized as forms of empowerment. "However, when women go down those roads they find they are at the greatest risk of living in poverty, which has been shown in research," she says.

Tony McCashin from the Department of Social Studies in Trinity College has a different view of the increases.

"The rise in the number of unmarried parents comes against the background of greater co-habitation, where living together has become an increasingly popular prelude to marriage," he says. When a co-habiting couple go their separate ways, a one-parent family is left behind. The pattern of co-habitation is particularly relevant to middle-class people, says McCashin, who has undertaken extensive research on lone mothers.

"The more controversial increase in the number of poor lone mothers can be explained by problems with the labour market," he suggests. In other words, the lack of opportunities for women with limited education and skills, creates a class of welfare-dependent single mothers.

However, he points out that the resurgence in the State's economic fortunes could change this historical pattern. He says the decision of unmarried women to have a child is not a case of "lying back and thinking of Ireland" and then waiting for the first welfare payment to arrive.

In terms of official policy, some have questioned the requirement that to qualify for one-parent family payment the recipient cannot be co-habiting with a partner. Several groups have expressed the view that such a rigid rule militates against joint parenting by mother and father.

As last year's final report on the Commission on the Family said: "the other parent (usually the father) cannot be acknowledged, he becomes marginal to his child's life and remains marginal to the family's life and role in the community". The report, predictably, did not suggest any concrete reforms in the area, but simply called for things to be kept under review.

While few bold actions are being taken, the escalating bill for one-parent family payments has forced Government to change policy direction. The new orthodoxy is to integrate lone parents who, as group, have only a 29 per cent labour participation rate) into the workforce.

Financial disciplinarians want this to happen as it will reduce the payouts by the State, while lone parent groups support the idea because it gives the people they represent a chance to improve their quality of life - and increase their financial means.

However, others have put a different complexion on the shift in policy. Pauline Conroy, from the Social Science Research Centre in UCD, wrote in a recent essay that "in a perverse sense this represents a full turning of the policy circle back to the mid-19th century, when they [lone mothers] were expected to fend for themselves and their children on the labour market".

The sharp increase in the number of separated parents (apparently across all classes), McCashin puts down to the narrowing gap between men and women's pay.

"The fact that women are now becoming more financially independent from their husbands and partners means they have greater choices in life." This includes the option to get out of a relationship in which they are no longer happy. He adds: "The modern financial framework between men and women gives women alternatives which weren't there before."