"Is my 18-month old already behind for schooling?" That was the subject line of a recent post on the D.C. Urban Moms and Dads online discussion forum. The anonymous author was reacting to an article written by a mom who had hired an education consultant to help her navigate the preschool enrollment process for her 6-month-old daughter. "Is this normal?" the listserv poster queried.

It's easy to dismiss this question as an example of the neurotic, competitive parenting of elite urban dwellers. But it's actually one that education and child development experts want more parents asking. Because the answer can depend on who is doing the asking and, more importantly, what economic stratum they live in.

I live in a "reviving" neighborhood in Washington called East Capitol Hill. Cab drivers once refused to take passengers here, but now the area is peppered with educated and relatively affluent newcomers, as well as lower-income families who weathered the darker years. About a year ago, I met a single mother from this latter category, roughly 20 years old, and her bright-eyed, 4-year-old daughter. She overheard a conversation between me and my son and was impressed by his vocabulary—or, as she put it, "the way he talks."

"Did you read to him?" she asked me. "Should I read to her?"

The answer, of course, is yes. The sooner the better. Reading aloud introduces more and different words into the vocabulary of both parent and child at a time when the child's brain is growing at its fastest. Researchers have found that 86 percent to 98 percent of a child's vocabulary by age 3 consists of words used by his or her parents. It's no wonder, then, that young kids of professional parents know twice as many words as the kids of low-income parents. By age 4, the average child in a poor family might have experienced 13 million fewer words than the average child in a working-class family. Between the highest and lowest ends of the economic spectrum, there could be a 30-million-word gap in children before they reach kindergarten, according to psychologists Betty Hart and Todd Risely, who published their findings in 2003.

My neighbor didn't know those statistics, and it was pretty clear that she wasn't worried about getting her daughter into a top prep school. Yet she intuitively knew that reading to her daughter was a good idea. She and millions of other parents share the same dilemma: How do we give our kids the best start possible when most of their early exposure to the world comes from us? It's a lot of pressure on parents, whether they dream of a future Rhodes Scholar or struggle just to keep their children fed and clothed.

Middle-income professionals like me generally muddle through parenthood (not always elegantly), unknowingly assisted by our own educations. Research says the more highly educated the parent is, the better a child's vocabulary and learning ability will be, almost automatically. So it's disadvantaged kids who could see the biggest gains from targeted early-childhood education. But that means that education should also target their parents, who may be pretty young themselves. A mother who has a baby at 17 will still only be 29 by the time her kid is 12. That's plenty of time to help her become productive in work and home. And once her child is grown, she has years ahead of her to contribute to the economy.

But that's not how benefit programs generally approach the problem, which means mother or child lose out. "We are really are in jeopardy of losing the earning potential of two generations at once," says Anne Mosle, executive director of Ascend, a division within the nonprofit Aspen Institute that is researching how government programs can integrate help for parents and kids at the same time.

This two-generation approach requires a shift in political attitude. "People are more willing to rally around children, many times more than low-income adults," Mosle says. "There is ongoing discrimination against low-income, single mothers. But when 50 percent of children born to millennials are born to a single mother, we need to have a different paradigm about what we do going forward."

University of Chicago economist James Heckman has placed a dollar value on early education for disadvantaged kids, saying investments give returns of 7 percent to 10 percent per year, per child. The money that would be spent to reduce crime later in those kids' lives would cost five times as much, he argues. The White House Council of Economic Advisers estimates that children who receive quality education before kindergarten will see an increase in their adulthood earnings of 1.3 percent to 3.5 percent.

Such dramatic statements have prompted renewed public policy interest in early childhood education. President Barack Obama on Wednesday convened some two dozen educators and policy experts for an all-day White House forum on the topic. The first five years of life is a "critically important window of opportunity to develop a child's full potential," said White House domestic policy adviser Cecilia Muñoz.

Advocates are happy about the attention, but given the clear evidence of the effectiveness of early-childhood education, they argue that the United States' ability to provide it is pretty weak. Fewer than one-third of 4-year-olds are enrolled in government-sponsored pre-k. If parents can afford it, many opt for private preschool. Still, the Census Bureau reports that only about half of 3- and 4-year-olds are enrolled in any type of "nursery" school, public or private.

3- and 4-Year-Olds in Nursery School and Kindergarten

Just over half of 3- and 4-year-olds in the U.S. are enrolled in either nursery school or kindergarten, with most of those attending either a public or private nursery school. (Source: U.S. Census Bureau, Current Population Survey, October 2013)

In Obama's 2013 State of the Union address, he said he wanted to give all moderate- and low-income 4-year-olds access to quality public preschool. On Wednesday, Education Secretary Arne Duncan announced $750 million in federal grants for 18 states to expand preschool access. Save the Children Action Network, a nonprofit group that is participating in the White House forum, is advocating for universal public pre-k, a $70 billion proposal that the group's lobbyists hope will gain traction in Congress next year.

Most education experts agree these are worthy endeavors, but they are still focused on 4-year-olds. And that's not early enough. It's not enough for my neighbor, who could have benefitted from information about reading to her child long before I told her about it.

The policy community, meanwhile, is maturing in its thoughts on early education, understanding that more doesn't necessarily mean better. "I think they're skeptical of many, many of the programs that are in place," says Kris Perry, executive director of the First Five Years Fund and another participant in the White House forum. "We can't hold all of these other programs blameless. We have to look at the amount of money going out."

Herein lies the dilemma. The country still needs more investment—a whole lot more—to really change the life trajectory of young kids being raised by poor, single moms. Yet not just any program will do. Research consistently shows that the effectiveness of a program depends almost entirely on the quality of the teacher. Some of the well-established government programs for early learners, like Head Start, do not always stack up. Thus, advocates find themselves in the tough position of pushing lawmakers aggressively just to embrace the issue, which is rarely anybody's top priority. But once they have the attention of policymakers, it's hard to then tell them that their favorite programs may not be up to par.

Katharine Stevens, a research fellow at the American Enterprise Institute think tank, is a perfect embodiment of this conundrum. She recently joined the conservative AEI with a specific mandate to poke holes in the ways that early-childhood programs, new and old, are implemented. If the new initiatives being rolled out by the White House are anything like the current public school system, she says, that's a problem.

From Stevens' perspective, the current K-12 public school system is adequate but certainly not a model that the country should replicate completely for younger kids. "There's almost $30 billion in the New York public school system that fails millions of kids," she said, by way of example.

Stevens also objects to what she says is an over-focus on 4-year-olds. Research suggests that nurse-parent coaching about caring for babies and toddlers is actually far more effective, and yet the social programs to provide those are in their infancy. A $1.7 billion federal maternal and infant home-visiting program was implemented in 2010, and Congress is expected to continue support it, but the program is only a small part of the administration's early-education initiative.

"If you really look at what the early brain-development stuff is saying, 4 is almost too late," she said.

Stevens is paid to be critical and ask tough questions about the effectiveness of government programs. And yet, when asked what she would recommend on her own, she had this to say: "If it were up to me, we would be spending billions and billions more dollars on early education."

It's a sentiment that most parents would agree with, from the wealthy family that pays a consultant to get its kid into an elite private preschool to the poor single mom who would welcome any way to get her child ready for school. The question then becomes how to harness that desire and turn it into action. Public opinion polls show a high level of support, Perry said. "But what we need is public demand."