Study after study has shown that having children does not make people happier. In fact, a so-called “happiness gap” exists between people who have kids and people who don’t, and parents often pay a “happiness penalty” when they have children, research has shown.

But it turns out, while this is true in America, it’s not true in other parts of the world. Recently, researchers studied data from 22 countries and found that the United States has the largest happiness shortfall between parents and non-parents, even larger than the gap found in similar nations like Great Britain and Australia. And in other developed Western countries, like Norway, Finland, Sweden, Hungary and Russia, the gap didn’t exist at all. In fact, sometimes parents were even happier than non-parents.

But why? That was the question Jennifer Glass, Ph.D., professor of sociology at the University of Texas, Austin, and a team of researchers set out to solve. Surprisingly, the answer had nothing to do with income level, whether the parents were married or not, or whether the pregnancy was planned or accidental.

Instead, Glass and her team found the key to parental happiness was one very specific thing: a country’s family-friendly policies (or lack thereof). “The negative effects of parenthood on happiness were entirely explained by the presence or absence of social policies allowing parents to better combine paid work with family obligations. And this was true for both mothers and fathers. Countries with better family policy ‘packages’ had no happiness gap between parents and non-parents,” the researchers report.

“We comprehensively tested every other alternative,” Glass told the New York Times. “The two things that came out most strongly in explaining the variation were the cost of care for the average 2-year-old as a percent of wages and the total extent of paid sick and vacation days.”

The study will be published in the American Journal of Sociology in September.

The heavy burden of child care costs

Daycare teacher with children Full-time child care at a daycare center can cost parents thousands of dollars a month. (Photo: Robert Kneschke/Shutterstock)

As any working parent knows, child care costs are astronomical. When my first daughter was born eight years ago, my husband and I looked into full-time daycare and were stunned to find out it would cost more than our mortgage each month. We couldn’t afford it, even with two salaries coming in. We managed by cobbling together a plan where I worked from home two days a week, she went to a daycare center two days a week and my father watched her one day a week. But we were lucky — what would we have done if my boss said no to my work-at-home request? What if we didn’t have a nearby grandparent willing to babysit for free?

Even if parents can afford the hefty cost of full-time child care, they still have one obstacle to overcome when it comes to enrolling the child: wait lists. High-quality child care centers can have waiting lists with hundreds of children's names on them — some not even born yet. The competition for high-quality care is so steep that parents are signing up as soon as they find out they’re pregnant. And if you're thinking of opting for a nanny, as we did with our second daughter (though ours is part-time), get ready to pay between $15 and $20 per hour for an experienced babysitter certified in CPR and first-aid. That's up to $800 a week!

Meanwhile in France, where working mothers report much higher rates of happiness than American mothers, according to the study, more women are having babies than ever before. And unlike the U.S., the French government has long-standing policies in place to support them. The Family Allowances Fund, which has been around since the 1930s, pays working mothers their full salary for 16 weeks of maternity leave (26 weeks if it’s her third child) and also gives them “family allowances,” where moms of little kids get a stipend from the government that they can use to pay for child care. (By the way, you may have heard that France has a great early childhood education program for kids as young as 2 months old with lots of child care options, and that they pay workers really well. That is sort of true, but not completely, according to this lengthy Forbes story.)

About that unpaid maternity leave

Pregnant woman working at the office When maternity leaves are shortened, the health of both the baby and the mother can be compromised. (Photo: VGstockstudio/Shutterstock)

The U.S. is the only developed nation in the world that does not mandate paid maternity leave. This is a rhetorical question, but how are parents supposed to afford those panic-inducing daycare costs after weeks of unpaid maternity leave? It doesn’t exactly help build a cushion in our bank accounts. With each of my daughters, I took about three months of maternity leave — some of it paid by using vacation time, but most of it unpaid. And again, I was among the fortunate ones.

At a previous job, I supervised a team of roughly 20 people, most of them full-time but some part-time, and those part-time workers did not get paid time off. I’ll never forget sitting across a conference room table from one employee, who told me she was pregnant and planned to take only three weeks off after the baby before returning to work. Her job was safe no matter how long her leave, but because it would be completely unpaid, she couldn’t afford it. Sadly, her story is not unique. A hairdresser in Nevada told The "Today" show that she took only three weeks off because of money. Some desperate expecting moms have even turned to crowdfunding sites to raise money for maternity leave, including a young single mother who works at a fast-food restaurant.

When maternity leaves are shortened, the health of both the baby and the mother are compromised. "Maternity leave from a job after childbirth provides critical time for maternal-infant bonding and adjustment to life with a new baby. Longer maternity leave is associated with increased breastfeeding duration as well as improved maternal mental health and child development," according to the U.S. Department of Health and Human Services.

A benefit for non-parents, too

If you don't have kids and don't plan on having kids, you may be thinking that none of this applies to you. Au contraire! The New York Times reports:

“That more paid sick leave and vacation time would make non-parents happier was no surprise, but “we were a little puzzled that lower child care costs would show an effect on non-parents,” Dr. Glass said. She and her colleagues speculate that the result is what economists call an indirect benefit: Everyone is better off when countries invest in the future of their labor force, and everyone suffers when they don’t.”

Angela Nelson ( @bostonangela ) is an exhausted mom of two young daughters and two old cats, and a Pulitzer Prize-winning digital editor with more than 15 years of experience delivering news and information to audiences worldwide.