When it comes to who is happier - parents or child-free people - most of the research up until now has concluded that it is the childless who are more satisfied with their overall lives.

As a married mom of two, I always find myself reacting a bit defensively to that research.

"I'm happy," I say to myself. I may be stressed, sleep-deprived and sorely in need of "me" time, but I am very satisfied with my life. Isn't it possible that I could be just as happy as someone without kids - even if they have more time to sleep and take care of themselves?

According to two new studies, the answer might be yes and no.

A report by Princeton University and Stony Brook University published in the Proceedings of the National Academy of Sciencefound "very little difference" between the life satisfaction of parents and people without kids, once other factors - such as income, education, religion and health - were factored out, said Arthur Stone, one of the study 's co-authors.

People with kids living at home tend to have more money and are more highly educated, more religious and in better health, said Stone, a professor of psychiatry and psychology at Stony Brook University. "All of those are factors that go along with people having better life evaluations."

Once those factors were statistically removed, the study found no difference in how satisfied the two groups felt about their lives.

Stone said in an interview that similarities in reported happiness among parents and the child-free, especially in developed countries like the United States, can be chalked up to priorities, specifically whether a person chooses to have kids.

"I choose an orange because I like oranges. You choose an apple because you like apples. There's no reason to think that your experiences should be any better than mine," said Stone. "The orange is different than the apples. Having kids is different than not having kids. It doesn't mean that one is ... intrinsically better."

Sarah Maizes, author of the children's book "On My Way to Bed" and a mom of three in Los Angeles, agrees. "It's like asking who's happier - people who like pizza or people who like Chinese?" she said on Facebook. "Now what I'd like to know is who lives longer. ... That you can measure!"

The Princeton-Stony Brook study - which involved an examination of a survey of 1.8 million Americans, including parents between the ages of 34 and 46, conducted by Gallup from 2008 through 2012 - did find one difference between parents and the childless: Parents tend to experience more highs and lows.

"They have higher highs. They have more joy in their lives, but also they have more stress and negative emotions as well," said Stone.

See full story at CNN.com