A few years ago, a pregnant scientist at Merck & Co. casually told her boss that she was going to have problems finding good child care after her baby was born.

Concerned that he might lose her services, her boss quickly wrote corporate officials asking if Merck had any plans to set up its own child care center.

That inquiry set the ball rolling, and eventually led the New Jersey pharmaceutical and chemical company to grant what it called a sizable sum to its employes to set up their own day care center a mile from the company's headquarters.

Today, the Merck employes' center has become a model for other companies considering corporate day care service. It has a waiting list of 72 families for its 58 spots, with women who are not even pregnant signing up to make sure there will be a place for their children when they are born.

The company's response to the employes is "indicative of Merck's willingness to listen to just a few people," said E. Jeffrey Stoll, manager of corporate personnel. "Merck listens to its employes, whether they come in a group of one or 100."

The willingness to listen and respond to Merck's 33,000 employes and their family needs has earned the company a good reputation among employe-relations experts. Along with a dozen other pharmaceutical and high-tech companies, Merck repeatedly is cited as one of the nation's leaders in trying to alleviate stress on employes as they try to balance the conflicts between work and family life.

"Traditionally, family issues and productivity have been considered like oil and water -- they don't easily mix," said Ellen Galinsky, project director of a work and family life study at New York's Bank Street College. "However, Merck, like some other pharmaceutical, high-tech and high-growth companies, has taken an unusual stance in thinking about the needs of the employe of the future and understanding these needs," Galinsky added. "These needs are not traditionally thought of as part of corporate benefits. But Merck realizes these needs are important in recruiting and maintaining employes and in satisfying workers and increasing their effectiveness. Merck's thinking in that way is unusual and a beacon for other companies."

In addition to the day care center, Merck offers flextime, permitting workers to tailor their hours to meet family needs. It also allows some workers who are on maternity leave the opportunity to work at home. Additionally, it participates in a job bank program with other New Jersey corporations to help locate jobs for the spouses of employes they want to hire. Company officials say spouse employment assistance is critical at Merck because scientists have a tendency to marry scientists -- making spouses all the harder to place.

More family-oriented programs are now in the works for Merck, the nation's largest pharmaceutical company. The company is studying a permanent part-time program for employes who want to spend more time with their families. Additionally, it is weighing a phased-retirement program for its older workers. An employe-assistance program to help workers cope with family and marital problems is also under way.

What's more, Merck plans to conduct an in-depth survey of employes at two Rahway divisions next year to find out where the potential for family-life stress is the greatest. "The whole reason for it is to come up with a better understanding of where we need to be more supportive of our employes," said Art Strohmer, Merck's director of human resources, planning and development. He added that he hopes the study will "lay the groundwork for some more programs."

Strohmer said that it would be nice to say that the company was being altruistic in offering these programs. But he acknowledged that there is really a more basic economic reason:

"It is good business to be interested in an employe's welfare and do whatever you can to make an employe's existence more fulfilled. If you help take away some of the stresses associated with family life, then when an employe comes to work, he or she will be able to put that much more attention to work. . . . We see a definite payback for being responsive. The better you are able to meet the needs of an employe, the more productivity you have."

Many more companies are going to find that they will have to offer these programs as more and more women enter the work force, according to Sheila B. Kamerman, a professor at the Columbia University School of Social Work.

Today, women account for about 44 percent of the labor force. By the end of the decade, they are expected to account for more than 45 percent. "This is in striking contrast to 38 percent in 1970 and 33 percent in 1960," Kamerman noted.

"The most dramatic increase in female labor-force participation rates during the last five years has been among women with children under age one; these rates have increased by almost one-third, from 32 percent in 1977 to almost 42 percent in 1982," she said.

With the government reducing its spending for social programs, the burden to alleviate the conflicts posed by the demands of work and family life will fall increasingly on the employer, Kamerman predicted.

"Becoming more sensitive to the needs of working families may be simply good common sense as these families come increasingly to dominate the work force," Kamerman said. And "it may be good for corporate image-building, too," she added.

Strohmer also is convinced that Merck's sensitivity to its employes' needs has produced economic benefits. Although he has no supporting data, he said that he believes the programs help to explain why Merck has one of the lowest turnover rates in the country, with about 5 percent of the work force leaving each year, compared with the nationwide average of nearly 20 percent.

He also pointed to a marked increase in productivity in divisions that use flextime. There is less absenteeism, and, in some divisions where there are not enough machines for all employes, flextime allows a division to use its equipment more efficiently.

Merck began offering flextime about four years ago after conducting a pilot study in two of its divisions. Today, flextime is available to the entire company, but it can be implemented only upon the approval of the division head. Under the company's rules, each employe must work 37 hours a week, and be at work between the key hours of 10 a.m and 3:30 p.m. The exact hours are flexible, so long as the employe has the same daily hours for at least one month at a time.

Strohmer estimated that at least two-thirds of the company uses flextime at some time or other. The divisions that still don't use it include those run by "the traditional-type manager who feels he has to be here when even one employe is at work," Strohmer said. "He doesn't want to be here from 7 a.m. to 7:30 p.m." Additionally, blue-collar workers have limited flextime because using it in processing plants would cause too much disruption in Merck's operations.

The cost for using the center is $520 a month for infants, aged 3 months to 2 1/2 years, and $329 a month for pre-schoolers. Although the pre-school tuition is competitive with that of other day care centers in the area, school officials admit that the price tag for infant care is somewhat high, especially compared with the cost of child care services provided by an individual in her home for a group of children.

Nonetheless, the child care center has become such a success that Merck has started another at its West Point, Pa., plant and is considering launching one at Calgon Corp., a subsidiary in Pittsburgh.

Implementing these programs has not been easy, according to Strohmer. "Providing programs that are supportive of life-style changes -- and especially family structure changes -- flies in the face of some very traditional -- and very ingrained -- American beliefs," he said. Among them is that "an individual's personal life situation is his or her primary responsibility, separate from the corporation," he said.

As a result, many managers have been reluctant to implement some aspects of Merck's new corporate philosophy, and some employes -- fearing an invasion of privacy -- have been reluctant to participate.

"There is a trade-off here," one employe-relations expert noted. "Merck is very supportive. But if they don't see your car in the parking lot by 8:30, they begin to wonder where you are. It's supportive, but very demanding."