The cost of child care – both to families and to the labor force – was a hot topic among Democrats in Wednesday's debate, taking center stage after the presidential candidates were asked how they would address the incredible price tag associated with providing care for young children.

Entrepreneur Andrew Yang used the question to tout his so-called Freedom Dividend plan, which would provide Americans with $1,000 each month that, he said, they could put toward child care.

In 30 states and Washington, D.C., the average cost of care for an infant exceeds annual in-state tuition and fees.

As it stands, more than 7 million children aged 3 to 5 attended an early childhood education program in 2017 – a significant increase over the last fifty years from 37% in 1970 to 64% in 2017, according to an analysis of government data by USAFacts .

Courtesy of USAFacts

Enrollment in publicly provided programs has outpaced private programs. The percentage of children enrolled in public programs in 2017 stood at 46%, compared to 18% enrolled in private programs – the majority of whom are enrolled in full-day programs.

That's largely been a result of cities like Washington, D.C.; New York, Boston, Charlotte, North Carolina; Nashville, Tennessee; San Antonio and others establishing and expanding free preschool options, especially for their lowest income families. Those efforts have occurred alongside slight increases to funding for the two largest federal programs , Head Start, which provides comprehensive services for low-income families with young children, and the Child Care and Development Block Grant program, which distributes funds to states to administer child care services.

Almost every candidate has backed universal early childhood education, some with more specificity than others.

Sen. Elizabeth Warren of Massachusetts, for example, has made the availability of child care a cornerstone of her campaign, retelling again and again the story about how she owes all her success to her aunt, who moved in with her to help care for her children when she couldn't afford quality daycare.

Warren's plan would provide free daycare for any family that makes less than 200% of the federal poverty line and "affordable" daycare for any family over that 200% threshold at rates that are capped at no more than 7% of that family's income. Under the proposal, the federal government would partner with local providers to create a network of child care options. Local communities would be in charge, but providers would be held to high national standards.

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Sen. Cory Booker of New Jersey, Sen. Kamala Harris of California, Sen. Amy Klobuchar of Minnesota and Sen. Bernie Sanders of Vermont are co-sponsors of a bill that would accomplish many of the same things as Warren's proposal, including providing more federal funding for infant, toddler and preschool programs and capping child care expenses at 7% percent of income for families earning less than 150% of their state's median income.

Notably, Democratic presidential contender Julian Castro, the former secretary of Housing and Urban Development for the Obama administration – who did not qualify for Wednesday's debate – pushed one of the first universal prekindergarten programs in the county while mayor of San Antonio.

The issue of providing access to childcare and prekindergarten programs has generated attention among policymakers as research shows time and time again how lack of access to such services hampers women's ability to return to work or progress in careers.

A recent analysis on the impact of Washington, D.C.'s program, which provides free access to prekindergarten to the majority of the city's 3- and 4-year-olds, found that it led to a 10% increase in labor force participation among mothers of young children.

Yang, who has a 4-year-old and a 7-year-old, one of whom is autistic and has special needs, also noted that the U.S. is one of the only countries in the country without a paid family leave policy, teeing up what would become the next question about candidates' plans for providing access to what the federal government currently doesn't provide at all.

The question was specifically directed to Klobuchar, who's proposed establishing a three-month family leave program, and Harris, who's proposed a six-month leave program.

As she's explained when asked about other expensive proposals like free college and the elimination of student loan debt, Klobuchar said she was careful in managing the economics of her plan.

"I'd love to do more," she said. "I'm just not going to go for things … just because they sound good on a bumper sticker and then throw in a free car. I think we have an obligation as a party to be, yes, fiscally responsible. Yes, think big, but make sure we have people's backs and are honest about what we can pay for."

"I just think we have to be smart," she said.

Harris, meanwhile, said her six-month plan takes into account the fact that people are having children in their 30s and 40s and, therefore, facing costs associated with childcare at the same time they're dealing with the financials of aging parents.

"What we are seeing in America today is the burden principally falls on women to do that work," she said, emphasizing that it's forcing them to walk away from careers that come with an important paycheck.