ABC News' Anna Wild and Juju Chang report:
Jessie Thompson is a professional photographer and mother of three who loves her children but admits being a parent is not all smiles and sunshine.
"For me, the lows are feeling sad when my kids feel sad," Thompson told ABC News.
"We are so self-examining that I think it creates a lot of guilt," she said. "Society is off-balance."
While Thompson's admission that the day-to-day grind of raising little human beings can turn happy people into less happy people is not what Hallmark movies are made of, her acknowledgement is what some experts call the "dirty little secret" of modern parenting.
That secret has been put into plain view in a new book, "All Joy and No Fun," by fellow mom Jennifer Senior, whose research shows kids don't necessarily make life fun.
Senior's book contains not just anecdotes from stressed-out parents, but scientific data that shows that parents' happiness levels are lower than non-parents.
The most difficult stages, Senior's research shows, are the early years and the teenage years. Both are stages where a child is fighting their parents for independence and parents are fighting to not let go of their children.
"The no-fun part I think people are much more reluctant to speak about," Senior told ABC News. "We know that there is some drudgery associated with parenting."
"I don't know if we are fully prepared to talk about how much anxiety we experience as parents," she said.
Senior believes that the digital age of Pinterest, Facebook and Instagram adds to mothers' feelings of guilt and inadequacy.
Her prescription is for parents to be realistic and a bit skeptical.
"Beware of someone who speaks with that great certainty about what they're doing," Senior said. "None of us know. It's okay to be uncertain.
Though Senior's data-driven research shows the struggles all parents face, the author says no scientific study can measure the long-term joy that comes with raising kids.
"Talking about fun is a very thin form of happiness. It is such a thin little layer," Senior said. "It's focused on gratification. Joy, it is very different. It's about a deep abiding connection to someone."
"I think parents report more highs [and] more moments of meaning," she said. "They report more structure and focus in their lives."