Since ancient times, wealthy people have been able to hand over child-care responsibilities to wet nurses and nannies. For working people, however, the need for professional child care began with the Industrial Revolution, when the location of work shifted to outside of the home. For decades, day-care arrangements were mainly informal and sometimes nonexistent. In late 19th century Chicago, for example, the social activist Jane Addams found that children were being left alone in tenements, sometimes tied to the leg of the kitchen table. Day care was one of the first missions of the Hull-House facility that she founded in 1889.

Development of the industry has perennially run up against the widespread belief that a child's own mother is the child's best caretaker. The resulting combination of social pressure and employer discrimination has kept many mothers out of the workforce, but poor mothers have not been able to afford the luxury of staying at home with their children and have struggled with the cost of high-quality day care.

The situation worsened since the last decades of the 20th century as stagnant wage growth and a high divorce rate have made it necessary for increasing numbers of middle-class women to work. They also have been heavily burdened by the cost of day care. In most states, center-based care of an infant exceeds 10 percent of the median income for a two-parent household and also costs more per year than a year's tuition and fees at the state college, according to Child Care Aware. As a result, even as increasing numbers of middle-class families are using day care for their children, many of them still rely on informal arrangements, and commercial day-care operations pay their workers low wages and sometimes even cut corners on the quality of their services to keep costs low.

One alternative for public policy, paying parents to stay home with their children, has come under attack for creating a culture of dependency. (Paid parental leave is a small concession to this goal, acceptable because the cost is borne by employers but limited geographically and in duration.) But the other alternative, subsidizing day care, has also met resistance because of the traditional nurturing-mother ideal and the specter of a literal nanny state.

Despite these objections, during the Great Depression the Works Progress Administration removed one of the barriers to employment in the few jobs that were available by funding emergency nursery schools for several tens of thousands of children. A decade later, America's entry into the Second World War required that large numbers of mothers go to work, and Congress responded by funding child-care centers that served about 600,000 children in areas where the defense industry was concentrated. With the war's end, however, federal funding ended and almost 90 percent of these day-care centers closed down.

Head Start, first authorized in 1965, was the first major child-care program aimed specifically at children of poor families. It was designed to improve the lot of these children by boosting their learning and health, providing social services for their families, and encouraging parental involvement. It now serves approximately 1 million children per year. In 1994, the program was expanded with the addition of Early Head Start, aimed at infants and toddlers.

Head Start is one of the programs funded out of the Child Care and Development Fund, which provides block grants to states and requires that states provide additional funding and adhere to federal guidelines for the child-care programs they can be applied to. In some states, child care is also funded from the Temporary Assistance for Need Families program. Industry critics consider federal guidelines to be very loose and note that state licensing standards vary greatly.

Presently, at least 60 percent of the costs of child care are shouldered by parents. A few states are now implementing universal preschool, which is meant to be available when a child reaches four years of age. The expectation, based on social science research that was known even as the wartime child-care centers were being shuttered, is that this public investment will be repaid when the program creates a more productive adult population in future decades.