And far from ideal it is. A large number of sociological surveys have looked at cohabitation and examined the results. A recent review of the research by Patricia Morgan, a British sociologist specialising in criminology and family policy, shows how striking the differences are between marriage and cohabitation. Her conclusion: marriage fundamentally changes the nature of a relationship. In summary, cohabitations are less stable, the couples are less faithful to each other, they have less money, poorer health, and are more prone to domestic violence. Not much of an argument for living together. But let's leave the couples for a moment, and examine the effects on children. In today's Britain, more than 20 per cent of children are born to cohabiting couples. There is a belief that when a couple living together have children, then their relationship must be committed and stable. Regrettably, this is not the case. As it turns out, cohabitations with children are more likely to break up than childless ones. Only about one third of children born to cohabiting couples will remain with both their parents throughout their childhood. High rate of break-up One study found that less than 10 per cent of women who have their first child in a cohabiting relationship are still cohabiting 10 years later. On the positive side, about 40 per cent will have married. But 50 per cent will be lone unmarried mothers because their relationship will have broken up. And cohabiting couples who subsequently marry are more likely to divorce, and to divorce earlier. All this means that children born to cohabiting parents are more likely to experience a series of disruptions in their family life, which can have negative consequences for their emotional and educational development. Children living with cohabiting couples do less well at school and are more likely to suffer from emotional problems than children of married couples. When a married couple divorce, or a cohabiting couple break up and there are children involved, one parent sometimes remarries, or moves in with a new person. (In some cases this cycle repeats itself leading to "serial relationships"). There are serious problems here for the children. Life outcomes are poorer: there is a greater tendency for children to run away from home, or to begin criminal activity. The informal step family is also an unsafe environment for children, with much greater risks of child abuse from the non-biological parent. Live-in or visiting boyfriends are the main problem. Civitas, The Institute for the Study of Civil Society, has published Patricia Morgan's book with the title, Marriage-Lite: The Rise of Cohabitation and its Consequences. Morgan says that finances might influence people's choice of cohabitation. For many people, especially those in low-paid or irregular work, getting married can seem too expensive. And some people feel that getting married is a high-risk gamble because no-fault divorce laws make it easier for a spouse to walk away from their commitment. Now, back to the effects of cohabitation on couples. Morgan says cohabiting relationships are fragile. They are always more likely to break up than marriages entered into at the same time, regardless of age or income. On average, cohabitations last less than two years before breaking up or converting to marriage. Less than four per cent of cohabitations last for ten years or more. Cohabiting also influences later marriages. The more often and the longer that men and women cohabit, the more likely they are to divorce later. Then there is the question of faithfulness. According to a national survey in Britain, both men and women in cohabiting relationships are more likely to be unfaithful to their partners than married people. Less prosperous At all incomes and classes in society, couples who are cohabiting accumulate less wealth than married couples. Married men earn 10 to 40 per cent more than single or cohabiting men, and they are more successful in their careers, particularly when they become fathers. For childless women, there is little difference with incomes. Whether they are married, single or cohabiting, childless women earn much the same. Differences arise when children arrive on the scene. All women who take time out of employment to care for children lose earning power. But compared with married women, cohabiting or single mothers often lack access to the father's income. Faced with relative poverty, they have greater difficulty in balancing their caring responsibilities with their careers. Couples living together have more health problems than married people. Because there is less commitment in the relationship, couples put up with behaviour which wives and husbands would discourage. This particularly involves smoking, alcohol and substance abuse. Couples living together are also much more likely to suffer from depression than married people. A woman living in a relationship is more likely to be abused than a wife. One US study found that cohabitation was the strongest predictor of abuse, ahead of race, age, education or housing conditions. Like most societies, marriage has had a special status in Britain, in society and in law. Marriage developed as a way to provide stability for families and for all of society. Marriage is a declaration of commitment which has public as well as private consequences. It is an institution which offers benefits not only to the couples themselves but to society as a whole. The commitment to an emotional and sexual relationship, to take care of each other, to stick with each other through life's ups and downs builds trust; it encourages spouses to make sacrifices for the good of the family. Traditionally, British government and society have supported the institution of marriage by giving it certain privileges and responsibilities, and by enforcing consequences for breaking marriage vows. The increase in divorce, and the rise in cohabitation has led to muddled thinking on the question of marriage. Jack Straw, when he was Home Secretary, opined "the most important thing is the quality of the relationship, not the institution in itself". Morgan says that in law, and in public debate the distinction between marriage and cohabitation has become rather fuzzy. If marriage benefits society, then we need to emphasize how it differs from cohabitation. Rather than allowing the status of marriage to be undermined, we should look for ways to strengthen it. Social Action is a Melbourne magazine of social affairs and commentary.