Cohabitation has come in from cold over the last 30 years and is now mainstream in modern nations, says a new report from the National Marriage Project at Rutgers University in the United States. In Sweden, Denmark, Norway and New Zealand cohabitors account for around one in four of all couples. In the United States the proportion is less than one in ten, but increasing. Cohabiting couples boost the numbers of births to unmarried women, which in France, Norway and Sweden now represent over 50 per cent of all births.

And yet ample research shows that the non-married lifestyle is not compatible overall with the wellbeing of children, says the report’s author, David Popenoe. “[A]ll the evidence we have shows that individuals fare best, both in childhood and in later life, when they benefit from the economic and emotional investments of their natural parents who reside together continuously and cooperate in raising them.” Popenoe has studied the data for some key European countries as well as Anglo outriders Australia and New Zealand, Canada and the United States, and has come up with some revealing results and interesting analysis. These include insights into the very low birth rates of Italy and Spain, and the famously high fertility of France.

Among his key findings is that cohabiting couples break up at a much higher rate than married couples, even in places like Norway and Sweden where cohabitation is institutionalised; and when they do marry, such couples are also more likely to divorce. Counting pre- and post-marital break-ups, the highest rates today are probably in Scandinavia. When it comes to birth rates, cohabitation generally slows the birth rate but this effect seems to be reduced as the lifestyle becomes more common and accepted.

Worst of all, however, are the “strongly negative effects of cohabitation and lone-parent families on child wellbeing”, says Popenoe, citing Swedish, Norwegian and British studies. Even in the countries with the most extensive welfare provisions, a substantial gap in child wellbeing remains between those children who grow up in intact families and those who do not. Popenoe suggests that only “a broad cultural shift” can reverse the situation, but he says governments can help by backing educational efforts to promote marriage, giving parenting and economic assistance to married couples with children, and not giving recognition to “new institutions that compete with marriage”. ~ Cohabitation, Marriage and Child Wellbeing: A Cross-National Perspective, National Marriage Project