If children’s natural parents are living together when they are born, does it make any difference whether or not their parents are married?

In the 2017 edition of the World Family Map report and essay released today by the Institute for Family Studies and Social Trends Institute, we explore that question, and more specifically, how the context of parents’ relationship at birth affects stability in children’s lives. After all, the world has changed a lot since the days when non-marital births generally meant scandal or shame for women who would either give their child away or raise that child without a partner. It has become increasingly common for non-marital births to occur to cohabiting parents rather than lone mothers.

For example, in the Dominican Republic, the share of all births to lone mothers stayed almost stable at just over 17 percent from 1991 to 2002, but the share of all births to unmarried women rose from 75 percent to almost 85 percent (cohabiting births rose from 58 to 67 percent). If the type of union children are born into—marital or cohabiting—makes no difference for children’s chances of growing up with both biological parents, then we might be concerned about stability in children’s lives in countries where births to lone mothers have been on the rise like Armenia, but not in countries where the share of children born to unions has been stable like the Dominican Republic.

In fact, the share of 11-year-old children living with both biological parents fell from 51 percent to 43 percent in the Dominican Republic from 2002 to 2013. That means the group of children born when cohabiting births were 10 percentage points less common were 8 percentage points more likely to be living with both biological parents at age 11.

Of course, much else can change over time besides what share of births occur to cohabiting parents. Therefore, we tested whether countries that experienced sharper rises in cohabiting births also showed sharper declines in shares of children reared by both parents with data from 68 countries across the world. And they did. For example, Figure 1 (below) shows that most countries have experienced a rise in cohabiting births and a decline in the share of children living with both natural parents later on (bottom right quadrant). There are also a handful of countries that have seen a decline in cohabitation and a rise in the share of children later living with both natural parents (top left quadrant). The countries where cohabitation is on the rise but stability in children’s lives is nonetheless growing are in the top right quadrant: they are scattered through Africa, Central/South America, Eastern Europe, and Northern Europe.


Overall, every percentage point increase in the share of births to cohabiting couples corresponded to a 0.27 percentage point decrease in the share of 12-year-olds living with both biological parents 12 years later. This finding is not as damning for cohabitation as much as a one-to-one correspondence would be: It essentially means that many of the cohabiting relationships are stable. But it also indicates that cohabiting relationships are less stable than marriage, and suggests that the growth of cohabitation leads to fewer children having the benefits of living with both parents.

For most countries around the world, the relative stability of cohabitation and marriage can only be tested using aggregate statistics like I have described above; therefore, we don’t know what proportion of cohabiting vs. marital unions fail in the first 12 years of children’s lives. However, richer data are available for many countries in Europe as well as for the United States. These data allowed us to test whether individual children born to cohabiting couples suffered more family instability than individual children born to married couples.

Unsurprisingly, we found greater stability among children born to married couples. But many who have paid attention to recent trends around this issue believe that family stability has more to do with family economics rather than marriage per se. That is, those with fewer resources are less likely to marry and also more likely to break up: Low resources affect both marriage and stability, and the link between them is much weaker than it appears.

In the overwhelming majority of countries, the most educated cohabiting parents still have a far higher rate of break-up than the lowest educated married couples.

To address that issue, our new World Family Map report documents the likelihood of breakup by union type separately for children whose mothers have low, medium, and high levels of education. We showed that children have more stable family lives when born within marriage regardless of their mother’s educational background (see figure 2 below). There were some countries like the United States and the United Kingdom where the advantage associated with marriage was smaller at low maternal education levels, but it was still quite sizable: children were 57 and 69 percent (respectively) more likely to see their parents split before age 12 if their parents were cohabiting rather than married at the time of their birth. So even if marriage matters less among those with lower socioeconomic status, it still has a large impact on stability for children. In addition, marriage mattered more rather than less among those with lower socioeconomic status in Spain, Belgium, the Netherlands, and Georgia.

Figure 2: Union Status at Birth and Subsequent Stability


Source: 2017 World Family Map

We found very few exceptions to the generalization that marriage is a more stable context than cohabitation for childrearing across 17 countries and three education levels. In 13 countries, marriage conferred a stability advantage at all three education levels, and Spain was the only country where cohabiting couples were more stable than married couples at more than one education level (both low and high: again see figure 2).

The Spanish example highlights what academics like to call selection: In a country like Spain where most births are marital, those who self-select into cohabiting births are atypical. The flip side of selection reasoning is that as cohabiting births become more normative, the couples having them become less select (more typical). Research on cohabitants in Europe has, in fact, found that they are more similar to married couples in countries where cohabitation is common than in countries where cohabitation is rare across a number of social and economic measures. Before our work in this report, the question remained: as cohabitation becomes more common, does it become more similar to marriage in terms of stability for children? Unfortunately, the answer is no. The stability advantage associated with marriage varies a lot between countries, but it is not smaller where cohabiting births are more normative.

In sum, the 2017 World Family Map contradicts three myths about cohabitation and family stability for children:

1) The first myth is that cohabitation is less stable just because poorer people are more likely to choose it. In fact, cohabitation is less stable than marriage regardless of the mother’s educational background. In the overwhelming majority of countries, the most educated cohabiting parents still have a far higher rate of break-up than the lowest educated married couples.

2) The second myth is that cohabitation becomes more similar to marriage as it becomes more widespread: That is not the case for children.

3) The final myth is that where cohabitation has been a long-standing alternative to marriage (scholars writing on Latin America and the Caribbean refer to a “dual nuptiality” system), further growth of the institution will not affect children’s lives. Again, that’s not the case.

Across the globe, the retreat from marriage seems to contribute to instability for children.

Access the full 2017 World Family Map here.