Growing up in rural Michigan, Nina Job got familiar with peers and people in her community following a "traditional trajectory." That meant "you go to college, you get married, you have 2.5 kids, you know — happy home, white picket fence type-thing," she tells CNBC Make It.

But moving to New York gave her a new perspective: "I remember being 20 and so surprised to meet single people much older than what I was used to ever seeing back home who were happy."

The varied domestic situations she encountered "opened my eyes to the possibility of so many different lifestyles, and just non-traditional family setups," the now-36-year-old says.

Now, Job is among the growing number of Americans who are choosing to live a child-free life. The U.S. fertility rate fell to a record low of around 1.6 births per woman in 2023, according to the National Center for Health Statistics.

Societies need to maintain a fertility rate of roughly 2.1 births per woman in order to sustain the population — in other words, to make sure there are enough people to keep the workforce up and running. Fewer babies can mean fewer workers, fewer taxpayers and, as a result, shrinking economies.

These demographic shifts have raised some alarms for economists, as well as certain politicians and public figures who frame the decline as indicative of moral decay. Not wanting kids is "a form of selfishness," the pope declared in 2022.

The reasons that more Americans say "no" to parenthood are more complex than they often appear, though. Becoming a parent is expensive, but money is not the No. 1 reason given for remaining child-free. In many cases, Americans simply have more options — and realize that they can pursue happiness in other ways.

"I think I was just raised on, 'This is what success looks like,' and it's this traditional family setup," Job says. "To be able to come out here and see it work 1,000 different ways made me realize I could have that."

Parenthood in the U.S. is expensive ...

Many Americans want children. Just over half of adults ages 18 to 34 without children say they are interested in having them, a 2023 Pew Research survey found. However, the responses don't break down evenly by gender: 57% of men say they want kids, but only 45% of women do.

For those who do want children but end up putting off or even forgoing parenthood, a prevailing narrative is that it's simply too expensive. Perhaps babies have become a "luxury item," a 2023 Vogue article pondered.

Raising a child in the U.S. is particularly pricey, and families can't count on much help from the government. "America's welfare system is pretty generous for the elderly, but relatively stingy for kids. Comparing the United States to almost 40 other countries in the OECD, only Turkey spends less per child as a percentage of their GDP," the NPR podcast Planet Money recently reported. 

The U.S. is, famously, the only wealthy nation that does not mandate any paid parental leave. Here, "only about a quarter of American workers — regardless of gender — have access" to it, according to Planet Money.

And U.S. parenthood has gotten even more expensive in the last couple of decades. Day care and preschool prices spiked by about 263% between 1991 and 2024, according to a KPMG analysis of Bureau of Labor Statistics data. The total estimated cost to raise a child in 2023 from birth to age 18 is over $330,000, according to a Northwestern Mutual analysis.

Still, just 36% of childless adults under age 50 say they couldn't afford to raise a child, Pew finds. An even smaller 12% of adults over 50 without kids say affordability was a deciding factor.

... but money isn't the No. 1 reason why Americans won't have kids

Of those under 50 who say they're unlikely to ever have children, 57% say they just don't want to, Pew finds. Other major reasons for being unlikely to have kids include wanting to focus on other things (44%) and having concerns about the state of the world (38%).

That's a stark difference from older adults. Among those over age 50 without children, 31% say they never wanted to, per Pew.

A large contributor to the declining birth rate in the U.S. comes from a drop in unintended pregnancies, the rate of which in the U.S. fell by 15% between 2010 and 2019, according to the Centers for Disease Control and Prevention. In other words, more people who don't want to become parents can avoid it, thanks to advances in contraception and reproductive technologies.

And an increasing share of adults under age 50 say they never intend to have children, a separate Pew study found. That group grew from 37% of adults in 2018 to 47% of adults in 2023. 

If costs aren't the deciding issue, why don't younger Americans want kids as badly as their own parents seemed to? For many, it's because the demands and requirements of parenthood itself have changed.

Parenthood looks daunting: We 'prefer not to be on the clock watching children 24/7'

Callie Freitag, 33, lives in Madison, Wisconsin, where she works as a public policy researcher, demographer and an assistant professor at the University of Wisconsin. She and her partner "arrived at the decision not to have kids because neither of us feel interested in being responsible for the care and feeding of small children," she tells CNBC Make It.

"We'd rather spend our time, energy and resources in other ways. We love being aunt and uncle, but prefer not to be on the clock watching children 24/7," she says.

Her goals include continuing to build her career, traveling and engaging with her community. Those are possible to prioritize with kids, she acknowledges. But "having children adds layers of complications."

"Having children is expensive, time-consuming and exhausting, especially in a country that does not adequately prioritize affordable child care or paid family leave," she adds.

Parenting culture has shifted over the last couple of decades, while millennials and Gen Zers were growing up and forming their opinions on what parenthood should look like. The mindsets of many people in those generations have changed accordingly.

No one wants to be a bad parent: There's 'a kind of general anxiety'

The stakes feel extremely high, and the concern about possibly messing up is real, Paula Fass, a cultural historian and professor at University of California, Berkeley, tells CNBC Make It.

"I do think that, right now, there is fear about child rearing and parenting, a kind of general anxiety that penetrates the younger generation. So they're conflicted about whether it's even worth having children, when so much is expected of you as a parent," Fass says.

Today's parents spend more time with their children than parents of yesteryear. Mothers in 2012 spent roughly twice as much time — an average 104 minutes a day — with their kids as moms in 1965 (54 minutes per day), a 2016 study found.

Meanwhile, fathers spent four times as much time on child-care duties in 2012 — an average of 59 minutes per day, up from 16 minutes in 1965.

The expectations to be "always on" when you are a parent can be discouraging or daunting to adults who want to have kids but also want to continue pursuing their careers, hobbies or other passions. That could contribute to a sense that would-be parents have to reprioritize their own lives, and even reshape their own personalities, if they want to have kids.

'You go online and there are 10 to 15 different perspectives'

Parenting doesn't just require more money and more time than it used to. Safe, trusted advice can be harder to come by.

Earlier generations of Americans had a singular national expert, Dr. Spock, who was widely regarded as a trusted source for parenting advice, Fass says. These days, "there's anxiety without an answer," she says.

"You go online and there are 10 or 15 different perspectives on what should be done about a particular [parenting] thing, and not only are there different perspectives, but there's a lot of slamming of the way people do things."

Parents may feel pressured to do everything in their power to give their kids a childhood they think will put them on a good path. The list of "musts" can include "gentle parenting," specialized schooling, elite sports training, state-of-the-art technology and more.

Brianna, a 29-year-old living in Connecticut, knew for most of her life she didn't want to be a parent and chose last year to get surgically sterilized. Her name has been changed for privacy concerns.

"It's something that I've wanted for as long as I've known that it was a thing," she says.

Nonetheless, it took years of documenting with her doctor that she was set on her choice before she got the greenlight to proceed with the procedure, Brianna says. When the Supreme Court decision overturning Roe vs. Wade came down and abortion restrictions went into effect throughout the country, Brianna's doctor became more willing.

In her case, adopting a dog four years ago helped solidify her choice to not become a mom. "The amount of stress I feel in making sure that she's living her best life and is healthy is not an amount of stress that I would want a child to have to deal with," Brianna says.

"I'm very neurotic with her," she says. "I know I would be even more neurotic with a human child."

Policy can only go so far to encourage reproduction

Declining birth rates aren't unique to the U.S. Countries around the globe have seen their birth rates begin to or continue to fall, as in the case of South Korea, which has the lowest fertility rate in the world.

Plenty of governments have taken steps to try to encourage their citizens to expand their families. South Korea increased a monthly allowance for families with newborns through their first year. Taiwan has introduced a cash benefit and tax break for parents as well as expanding its paid family leave compensation.

Few of these policy solutions have made a significant difference. Even countries like Norway, which are known for having robust family support policies, have started to see birth rates decline.

To a certain degree, that's expected, Jessica Grose reports for the New York Times in an essay titled, Stop panicking about the birthrate. "There's a pattern that occurs when both incomes and quality of life go up; societies move 'from lots of births and lots of deaths to fewer births and longer life expectancies,'" she writes, citing demographer Jennifer Sciubba.

"In addition, the more educated a population is, the more both men and women tend to delay becoming parents and have fewer children overall," Grose writes. "It's tough to argue that more education and longer life expectancies are bad things for humanity."

Whether something needs to be done about this situation at all on a policy level is debatable. "There are several reasons not to worry about falling birthrates," writes demographer Leslie Root for the Washington Post. After all, "the U.S. population has continued to grow over nearly four decades of sub-replacement fertility rates," she writes.

For individuals, of course, the decision to have children remains a highly personal one. And the Americans who increasingly prefer to opt out of parenthood may still be pro-family or pro-child in general.

"I love kids," Job says. "I want to be able to help other people with their kids in moments where they're really struggling."

"Seeing how much work went into [having kids] from such a young age, I was like, 'This is a lot,' and you have to decide at some point," she adds. "You can have anything you want. You can't have everything you want."

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