Charles Fain Lehman of the Washington Free Beacon reports on recent research involving children and parents’ happiness.

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.