Are people with children happier than people without? In the United States, those with and without children rated their lives about the same, but, globally, children tended to diminish well-being, according to a study released this week. The results were derived from two surveys by Gallup that included almost three million people worldwide. One survey covered nearly 1.8 million Americans from 2008 to 2012 and the other interviewed 1.07 million people from 161 countries between 2006 and 2012. Participants were asked how close their lives were to being ideal, and what kinds of emotions they felt the previous day. Potential responses included happy, sad, angered, worried or stressed. Parents reported more ups and downs than non-parents. Those with children at home reported higher levels of all the emotional responses, including happiness and stress, smiling and anger. When researchers took into account other attributes that parents tended to have - higher education, more income, better health and religious faith - they found similar levels of life satisfaction as reported by non-parents. On the whole, both US groups rated their lives about the same on a scale of one to 10. Adults of all ages with children at home rated their lives 6.82, while the childless came in at 6.84. When researchers looked solely at people in the prime child-rearing years, ages 34 to 46, they found people with children rating their lives at 6.84, just higher than those without at 6.51. In the rest of the world, the survey results told a different story: people with children, at least those outside the rich English-speaking world, tended to be less content. "Our results for the world as a whole, as well as for Africa, Latin America, the Middle East, and South Asia are consistent with the most common finding in the literature - that those with children have lower life evaluation," the study, released on Monday, said. "The higher the fertility rate, the more likely are people living with children to report lower life evaluation than those who do not." In poor countries, personal happiness may take a back seat to necessities, like requiring extra bodies to work the farm, the study said. "Because of social norms, or pressure from their own parents and communities, or because of the productive contributions of children, people may have children even when, on a purely personal level, they would rather not do so," it said. "The take-home message is, 'Do what you want to do'," Princeton economist and lead author Angus Deaton said. "If you think children would make you happy, it's probably true. The study appears in Proceedings of the National Academy of Sciences .