The 40-year-old businessman, a genial but often harried working father of three (whose wife also works full-time), arrived late for work recently, his smallest son in tow. He spent the next half-hour on the phone trying to hammer out a child-care plan for the remainder of the day.

Exasperated, he exploded. "Our entire careers, not to mention our whole family income, currently depend on two 13-year-old girls. It's unbelievable the power they have over our lives."

This time, he managed. But his questions nagged: "What happens when our sitters don't consider babysitting a real job any more? Or when they get sick? Or when they just don't show up?"

That doesn't happen to Barbara and Ralf Hoherz of the German Democratic Republic. Like all working parents in the GDR, they have access to a nationwide system of free child-care centers and kindergartens.

Joseph and Marie-Therese Lay of France, like all French working parents, have substanital family allowances and a free, public pre-school system for all children 3 to school age.

Thirty-eight-year-old Kersten Pehrsson, like all Swedish working parents, has guaranteed paid childbirth leaves, paid days off to care for sick children and the right to work part-time with full job security.

There are, of course, major differences between 220 million Americans today, 53 million French, 17 million East Germans and the 8 million Swedes, not the least of which are differences of sheer size.

The United States, unlike France and the GDR, faces no "demographic panic." Put harshly, this means that there is no overwhelming economic need for the United States government to adopt so-called "natalist" policies which would attempt to encourage people to have children, policies which in Europe take the form of financial aid, long childbirth leaves and various government supports for child care.

The United States, unlike Sweden and the GDR, has no serious labor shortage; indeed the United States, like France, is faced with a serious unemployment rate. Put harshly, this means that there is now -- unlike during the World War II era -- no overwhelming economic need to entice women into the labor force by offering child care, maternity leaves and the like.

And unlike most European countries, the United States has a relatively short tradition of a welfare state, or Social Security programs in general. "Welfare," in fact, is practically a dirty word in the United States.

The United States has traditionally held as sacrosanct the right of business to function virtually unfettered by government. Whether one believes this good or bad, the result is that a business, say in Sweden, does more for its working parents than an analogous business in this country.

Given the differences, would it work to transplant the idea of the French preschool or the East German public kindergartens to the American scene?

To partially copy the Swedes by providing secure, part-time work for parents? Or paid days off to care for sick children?

Or to provide, across-the-board, paid maternity or paternity leaves of six months, as do most European countries?

No one, of course, knows the answers. But it is possible to speculate.

If, for instance, American kindergartens were extended downward to take all 3-, 4- and 5-year-olds, several things might happen:

The current surplus of teachers might be retrained and hired for preschool education.

Space in school buildings now under-utilized because of widespread declining enrollments could be used for preschoolers.

With a universal -- though not compulsory -- preschool system for 3-, 4- and 5-year-olds, half of the child-care problem might be solved, leaving only that of care for children between several months and age 3.

As with any social change, though, there are likely to be problems. Unions might fear the institutionalization of part-time work as a threat to full-time labor. Non-parent workers might oppose such flexibility for parents.

And feminists, who correctly report tht it is primarily women who take the part-time jobs, might express the fear that the institutionalization of part-time work could further solidify the double burden for women.

If the United States guarenteed fully paid parental leaves at childbirth -- as most of Europe does -- and paid days off to care for sick children, who would pay? Would the non-parent sector of the population be willing to raise taxes to support parents? Would business be willing to offer parental leaves as a benefit?

The mood of the country currently suggests a resounding "no" to those questions -- and yet there is a huge pool of American workers/parents beginning to demand more loudly that the world of work make their double lives more viable.

At the fractious White House Conference on Families this summer -- which had difficulty coming to consensus on many issues -- delegates resoundingly agreed on one thing: 93 percent said this country needs more family-oriented personnel policies involving parental leaves like European families', shared and part-time jobs and flex-time.

Already, according to business professor Stanley Nollen of Georgetown University, 6 percent of the United States work force flexes its hours, according to 1977 figures.

By 1990, predicts Nollen, 30 percent of the United States work force will use flex-time, an innovation for which, Nollen's studies show, there is a 50-50 chance of improvement in employee productivity on the order of 5 to 15 percent.

By 1990, according to the Urban Institute, instead of the present 6.9 million American preschool children with working mothers, there will be 10.4 million. And by 1990, only 25 percent of two-parent families will have one parent at home to care for children, compared to about one-third today.

(These figures have a double meaning. Not only does this massive influx of mothers into the work force create a huge potential demand for child care, it also simultaneously dries up much of the pool of traditional childcare providers.)

Whether Americans transplant some of the ideas of European countries, or whether Americans come up with their own solutions, it is undeniable that for both mothers and fathers in the work force, meshing the two roles of worker and parent is one of the most serious problems still facing this country.

Overall, according to a variety of studies, what American working parents, particularly the parents of infants and toddlers, want is a wide choice of types of child care, and money to help pay for it.

"A range of alternatives should be abailable, including pre-kindergarten, family day care, kindergarten and nursery schools, in-home care and center-based day-care programs," says the National Research Council, in its book, "Toward a National Policy for Children and Families."

"The programs should be available free or at costs that do not require the sacrifice of other essential goods and services."

Overall, says Jan Calderon Yocum, executive director of the Day Care and Child Development Council of America, a conservative estimate is that a minimum of 1 million childcare slots will be needed in the next five years in all types of care.

The National Campaign for Day Care for Working Parents, an advocacy group, goes even further: "Day care should be available to all parents who want it and need it at a price they can afford."

Joyce Miller of the Coalition of Labor Union Women and now a vice president of the AFL-CIO puts it even more strongly:

"I represent those women who have no choice but to work. There will be more than 10 million women entering the labor force between now and 1990, the majority, mothers of young children. . . What is going to happen to child care?

"You will not see adequate child care in this country until the United States government is willing to invest in its children."