When it comes to bringing a baby into the world, we might want to rethink the term "bundle of joy."

Study after study has shown that nonparents are happier than parents in the United States.

The happiness gap has less to do with children themselves and more to do with how this country's policies support parents in dealing with the costs of parenthood: namely, time, money, and energy, according to new research from the University of Texas.

UT researchers examined data from 22 European and English-speaking countries and the results of two international surveys to ask why American parents are less happy than nonparents.

Sociology professor Jennifer Glass revealed the surprising results:

The bad news is that, of the 22 countries we studied, the U.S. has the largest happiness shortfall among parents compared to nonparents, significantly larger than the gap found in Great Britain and Australia.

In other words, when compared to other countries, American parents are the most miserable relative to nonparents.

What's up with that? There are two main reasons for the significant difference in the happiness gap between the United States and other countries, Glass told The New York Times:

1. "The cost of care for the average two-year-old as a percent of wages" 

2. "The total extent of paid sick and vacation days”

Other nations offer more family support, such as extended paid parental leave, flexible schedules, and monthly child allowance payments. "Policies that made it less stressful and less costly to combine child rearing with paid work 'seem to be the ones that really matter,'" the Times reported.

Raising children is no doubt expensive: The projected cost of rearing a child through the age of 18 in the United States — including food, housing, child care, and education — is $245,340.

What didn't affect a parents' relative happiness? Economic differences, marital or relationship status, and whether the pregnancy was planned or not.

The dismal U.S. parental happiness gap is a warning to the government to establish more family-friendly policies. Wouldn't we rather be No. 1 in the world when it comes to happy parents?

[h/t The New York Times]