Does having kids make us happier? Yes, a new paper argues—once you control for the cost of paying the bills.

The way that kids shape their parents' happiness has been the subject of academic debate for some time. One school of thought argues that having kids should make us happier—otherwise, why would people keep doing it? Another argues children put a damper on parents' free time and financial resources, and are therefore net negative for emotional well-being.

Interestingly, the bulk of available data seem to side with hypothesis B, or at least find that there's no significant effect of childbearing on overall happiness. This finding may make many anti-natalists cheer. However, for the more scientifically minded, the question becomes why, exactly, this is. Do kids actually make their parents unhappy? Or are there some other, unseen factors which explain the so-called parenthood gap?

There is at least one big one, write economists David Blanchflower and Andrew Clark: Children make it harder for parents to pay the bills.

"Children are expensive, and controlling for financial difficulties turns almost all of our estimated child coefficients positive," the pair write in their new paper. "We argue that financial difficulties explain the pattern of existing results by parental education and income, and country income and social support."

To reach this conclusion, Blanchflower and Clark looked at ten years of data from Eurobarometer, an opinion survey of Europeans that has asked about presence of children in a respondent's household annually since 2009. Their analysis covered results from more than a million Europeans.

First, the pair replicated the standard finding that children in the household is associated with lower self-reported life satisfaction, although they note that the effect size was quite small. They find that this finding persists even when adjusting for certain socioeconomic variables.

"The happiest group in the first column are the married with no children," the paper explains. "Every other group has significantly lower life satisfaction, controlling for [a set of variables]."

However, the negative effect of having children disappears—and children in fact become positive—once Blanchflower and Clark control for a single important factor: how hard it was for their parents to pay their bills.

Respondents to Eurobarometer are asked if in the past year they had struggled to pay their bills at the end of the month. When Blanchflower and Clark controlled for this variable, they found that the negative effect of children on happiness reversed, becoming positive.

"Controlling for financial difficulties we then find that children now increase happiness," the two write. "Why else would you have them? This appears to solve the puzzle in the literature."

This finding is fairly intuitive—parents love their kids, but not the financial burdens that come with them. In "solv[ing] the puzzle" of why kids make parents unhappy, Blanchflower and Clark point to an important lever available to policy makers who want to improve the lot of parents, especially to encourage more childbearing.

That is because there is a strong connection between how expensive it is to have kids and how many people choose to have them, or how many kids parents choose to have. American childcare costs have risen to monumental heights, helping to explain plummeting fertility. As policy analyst Matt Bruenig recently noted,""half of poor adults who live with children are only poor because of the expenses of raising children"—meaning that the cost of childcare not only suppresses fertility, but also drives Americans into poverty.

Parents the world over want to have more children, and the new paper indicates that they would be happier for doing so—except, that is, for the expense. Obviously, that Blanchflower and Clark's work focuses on Europeans limits its applicability to the American context. Still, it would make sense for their insight to apply across the Atlantic.

What that means practically is that to make childrearing more appealing, governments do not need to talk their citizens into liking their kids more—they just need to make it easier for parents to pay the bills. Pro-family transfer policies are increasingly popular on both the left and right, with congressional Republicans floating Paid Family Leave proposals and 2020 Democrats rallying around universal Pre-K.

Such proposals, the new paper indicates, would not only help alleviate child poverty and encourage fertility. They would also make Americans happier with kids than without.