The Post's "instinct" {"Babies," editorial, June 4} is to support legislation calling for mandated family leave, admittedly with "some uneasiness," since the costs to business are unknown. The bill is one of several mandated benefit proposals -- with unknown costs -- on a fast track in Congress. While intended to help workers, these bills are no gift -- the unavoidable price will be lost jobs, lowered productivity and reductions in existing benefit packages.

There is no doubt that 18 weeks of leave for the birth, adoption or serious illness of a child, as mandated in the Family and Medical Leave Act of 1987, would be an excellent benefit. But what if a company is forced to cut back on other benefits in order to offer it? How does 18 weeks of leave stack up against a health-care plan that covers dependents? How does it stack up against a job?

The benefit pie can only be stretched so far. Many businesses today already are near the breaking point, as they struggle to compete in an international marketplace marked by a $170 billion U.S. trade deficit. It is courting trouble to load massive new costs on industry -- especially small business, which has generated nearly 70 percent of the nation's new jobs since 1982.

And there will be costs. Proponents argue that the family leave proposed is unpaid, but businesses would have to continue health benefits for absent workers, recruit and train replacements or double the workload of existing employees -- and pay in overtime and reduced productivity. A company's ability to adjust would depend in large part on its size -- but under this bill, companies with 15 employees are subject to the same mandates as companies with 15,000.

Employers are not blind to the fact that women are a sizable portion of the labor force -- 44 percent and growing. Successful employers are savvy enough to realize that family benefits are a terrific recruitment and retention tool. More and more companies are offering innovative programs such as flex time, parental leave and child-care vouchers to help workers cope with family/job responsibilities.

The key is flexibility -- flexibility to tailor benefit packages to meet the varying needs of differing work forces and to allow businesses to grow and prosper. Costly legislated mandates will stifle business expansion. Why not focus our energies instead on creating more jobs and prosperity? A better standard of living will do more for our workers and families than any combination of benefits. ALEXANDER B. TROWBRIDGE President, National Association of Manufacturers Washington

It isn't only "babies" that would benefit from the passage of the Family and Medical Leave Act of 1987.

An estimated 5 million Americans now care in some way for older relatives and friends as well as for spouses. These individuals provide between 80 and 90 percent of the medically related care, personal care, household maintenance, transportation and shopping assistance needed by older persons.

While the role of care giver is a rewarding one, it can also place great physical, emotional and financial burdens on individuals and families. The cost to care givers -- in terms of their own sense of well-being, health, employment and financial security -- may be high, often too high. And there is increasing evidence that care-giving-related stress may be having an adverse affect on industry in terms of increased absenteeism, higher error rates and lower productivity, and greater utilization of employee medical benefits.

The Family and Medical Leave Act recognizes the contributions and needs of the growing number of Americans who must care for their families and work at the same time. It recognizes that this phenomenon will become more significant as the number of older persons continues to increase. For these reasons alone, it is worthy of passage. CYRIL F. BRICKFIELD Executive Director American Association of Retired Persons Washington