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The link between fertility and marriage worldwide

Stable, long-term relationships are as important to fertility as ever, and policies to boost fertility that ignore that are likely doomed to fail

SHARE The link between fertility and marriage worldwide

Alex Cochran, Deseret News

As nations worldwide confront falling fertility, they often ignore what’s happening to marriage patterns on the theory that marriage and births are no longer wed. Worldwide, the number of births to unmarried mothers has been rising.

But a new report from the Institute for Family Studies and the Wheatley Institute at Brigham Young University argues that it’s impossible to promote fertility effectively without also promoting marriage.

Fertility has become an international concern as rates have fallen around the globe. The share of countries below the replacement rate of 2.1 births per woman of childbearing age is growing. That fact portends challenges not just for family life across the lifespan, but for economies, education, retirement, entrepreneurship, safety nets, workforce needs and more.

The report, “Marriage Still Matters: Demonstrating the Link Between Marriage and Fertility in the 21st Century,” looks at tens of thousands of fertility histories spanning almost a century to see the impact marriage and fertility have on each other.

Lyman Stone, research fellow at the Institute for Family Studies, and Spencer James, a Wheatley fellow and associate professor of family life at BYU, asked two seemingly opposite but actually closely related questions: whether women are more likely to have a first child once they marry and if having a first child increases the likelihood a woman will marry.

The report finds that worldwide, marriage “dramatically” raises the likelihood a woman will have a baby. Marital births are even better predictors of fertility than nonmarital births, the report says.

According to the research, ignoring marital status as significant to fertility rates is not constructive because they are so connected “that it is virtually impossible to promote marriage or fertility alone without also influencing the other.”

Stone said the linkage remains as strong statistically as ever.

The disconnect between marriage and fertility is recent, according to James. Historically, age at marriage has been a useful proxy for fertility patterns, a useful indicator “precisely because marriage and childbearing were so closely linked,” although birth control had great impact.

“We might be throwing the baby out with the bathwater by throwing marriage aside,” James added. “Importantly, we’re not talking marriage as legally binding relationships so much as we’re talking about marriage as one representation and certainly the most common representation of long-term, stably committed relationships.”

The researchers said that in countries where unmarried childbearing helps boost fertility a lot, “long-term, committed unions” that are similar to marriage are typically the context.

Study findings

As they pored over fertility patterns and records worldwide, the duo found:

  • In the United States, the odds of marrying grow when a woman gives birth. And the odds of giving birth grow when a woman marries.
  • In OECD countries, later marriage tends to mean lower fertility, while births outside of marriage don’t completely make up for the lost marital births. (OECD is the Organisation for Economic Cooperation and Development and includes 38 member countries.)
  • What people think they know about fertility in Asia is wrong. Although women there seldom have children outside of marriage because of stigma, marital fertility is also “unusually low, suggesting that factors broader than stigma against nonmarital fertility must be” the driving force of low fertility, per the report.

Countries with low fertility — both marital and nonmarital — like southern Europe and southeast Asia, that want to boost fertility “aren’t going to achieve it simply by trying to tackle some specific stigma on nonmarital fertility,” Stone told the Deseret News. “They’ll have to do it by really broader efforts to address labor conditions and the kinds of working hours and wages that people can expect to have.”

Those can dampen confidence that having and providing for a family is possible. According to James and Stone, those countries’ leaders should consider “improvements in housing, education, labor and social, familial and economic conditions.”

Stone told the Deseret News that people would probably be “more inclined to have children if their governments created policies to improve the quality of life for young adults and families.”

The report also points out that married women have “significantly” more children than unmarried women, even in countries that have a lot of nonmarital fertility.

The study doesn’t prove causation. Instead, the authors write that “because marriage and childbearing are linked in individual minds and plans, desire for children can motivate marriage, even as desire for marriage can motivate childbearing. But causality running both directions should not be construed to mean that the existence of either causal pathway is in doubt. It is clearly the case that changes to fertility or marriage behavior cause changes in the other behavior.”

The study notes that countries that have higher fertility outside of marriage — like the United States, France and Sweden — also have higher fertility among those who are married, so nonmarital births are not what makes the difference.

Policy implications

The study concludes that policymakers hoping to bolster fertility “should be careful not to disregard policies that affect marriage.” Whether new programs and policies “alter the total costs and benefits of marriage and union formation” will have an effect.

They write that “because nonmarital fertility is not required for a country to achieve high fertility and economic prosperity, policymakers should be cautious about diverting resources toward supporting single parents as a strategy for boosting births.”

Stone said they hope that those coming up with policies designed to stabilize and bolster fertility will realize “you can’t just throw money at sort of the marginal decision to have a child without first thinking about all the decisions in life” that lead to that point.

“Context and particularly long-term stable relationships still matter for childbearing,” said James. “And as soon as you try to separate those two, you're probably going to have less success than you were expecting.”