Few experiences are as wrenching for a parent as feeling rejected by a child. Yet in countless homes and day care centers at the end of each workday, says child psychiatrist Stanley Greenspan, "the parent, usually the mother, goes to take the child from the substitute caregiver and the baby gives her the cold shoulder."

Typically feeling some ache from missing her child all day, the mother often overreacts to what is essentially a common infant behavior, Greenspan says.

"Instead of realizing that the child just needs a little time to make the transition from sitter to mother," he says, "she takes the child's behavior personally and thinks, 'Junior doesn't like me.' "

She's likely to do one of three things:

withdraw from the child;

spend a frantic evening of intense "quality time" with the baby; or

quit her job.

None of which, he notes, satisfactorily solves the problem.

This common conflict between an adult's two major life pursuits -- love and work -- is "tearing women to bits in this country," says Boston pediatrician, professor and author T. Berry Brazelton. "Most women today are torn by this conflict about 'What am I going to do when I have to go back to work and leave a small child in somebody else's care?' And I think women who are staying at home are being torn in the same way about 'Should I be out in the work force?' "

This dilemma is often most intense for the increasing number of mothers who stay home with their babies just weeks or months before returning to work. "The number of mothers returning to work while their babies were less than a year old increased by 95 percent between 1970 and 1984," says the Ad Hoc Day Care Coalition in its new report, "The Crisis in Infant and Toddler Child Care." "At these rates, by the year 2000, four out of every five American infants under 1 year will have a mother in the labor force."

Most of these mothers must work for financial reasons, Brazelton says, yet "there is still a strong bias against mothers leaving their babies in substitute care unless it is absolutely necessary." Although employed mothers have replaced non-employed mothers as the norm, he says, "in the back of young mothers' minds a nagging question tends to persist: Is it really all right for mothers to work?"

This question may reflect "the age-old, commonly cherished image of the 'perfect mother' -- at home taking care of her children," says Brazelton. "We need to tell these mothers that, at a certain age, babies get what they need from other caregivers and that they, the mothers, will be able to stand the separation without feeling too grieved at the loss."

The age at which children can separate from parents and the precise effect of that separation are currently under study by a number of researchers. While past attempts to gauge the effect of maternal employment on infants have been "inconclusive -- they say it doesn't matter at all or that it matters too much," Brazelton says, "what worries me is the adults.

"When a new mother must share her small baby with a secondary caregiver, she will almost inevitably experience a sense of loss . . . They are apt to feel sad, helpless, hopeless, inadequate to their babies." To protect themselves from those painful feelings, they are likely to turn off the emotional development that commonly occurs when a woman becomes a new mother. And that, he says, "can be critical to the babies."

One of the solutions "which has been very positive," he says, "is pushing fathers in to fill the gap . . . But that's putting men into the same sort of conflict that women are in -- do I nurture or do I work? Can I do both?"

The result of these mixed messages, both from within and from society, he says, is that "the most subtle, hard-to-deal-with pressure on young adults comes indirectly, from society's ambivalent and discordant attitudes" about combining children and careers. That "creates a void of values, making the building and nurturing of a family very difficult."

Repeated experiences with parents "straining within their ambivalence" prompted Brazelton to write his just-released book, "Working and Caring." Over and over he is meeting women with high-powered careers and financial responsibilities who are stunned to discover the visceral depths of their bond to their babies and the pain involved in peeling themselves away from their infants to return to work.

One 37-year-old attorney with a 5-month-old son told Brazelton: "I have no good role models to follow as a mother who must go back to work . . . I'm a woman without a culture." That anguished cry led him to "explore the feelings of both men and women as they attempt to divide themselves into two important roles."

Brazelton is one of dozens of child development experts studying what infants need to thrive in today's complex society. At least six major books have been published within the past two years on that topic, and their divergent advice underscores the ambivalence over working and parenting:

*"Babies thrive with good day care, just as they do at home with an attentive mother," concludes University of Virginia psychology professor Sandra Scarr in "Mother Care/Other Care," which won the 1985 National Psychology Award for Excellence in the Media. "In fact, children are usually better off with satisfied substitute caregivers and a happy part-time mother than with an angry, frustrated full-time mother."

*"When both parents work, especially in nonroutine, professional positions, it's too often the case that the mother and the father have to cut corners with their children every day," writes Deborah Fallows in her just-released semi-autobiographical book, "A Mother's Work." A Radcliffe-educated linguist who left a promising career to stay at home and raise her sons, Fallows details the "chilling benign neglect" in day care and contends, "Children are, in large part, bearing the brunt of being accommodating in all these arrangements."

*"Can a woman decide to take on and competently carry out two roles at once?" Brazelton asks in "Working and Caring." "I certainly think so, and it seems time for us to face this fact as a national trend." Since parents are crucial to development of newborns, he says, government and industry should subsidize a leave of at least four months for new mothers and one month for new fathers to strengthen attachment ties within the family and perhaps "begin to reverse the national trend toward divorce and instability of attachments."

*"Full-time substitute care for babies under 3 years of age, and especially for those only a few months of age, does not seem to be in the best interests of babies," writes early education specialist Burton White in the 1985 revised edition of "The First Three Years of Life." "After more than 25 years of research on how children develop well, I would not think of putting a child of my own in any substitute care program on a full-time basis during the first few years of life."

These disparate theories about the impact of maternal employment on children can be legitimate or not "depending on the individual and the circumstances," concludes Dr. Benjamin Spock, guru to millions of parents for his classic book, "Baby and Child Care."

Babies need "happy, thriving, nurturing parents," he says -- three qualities that may be related to whether or not the parents are employed. A crucial factor is the experience the child has while the parents are at work. "If you can get good daycare between the ages of 2 or 3 and 5, it can actually add things very few families can offer," he says.

"Before the age of 2 or 3 is tricky, but good care would have preferably not more than three babies for every one adult."

What matters to a baby is not necessarily whether his or her parents both work, says child psychiatrist Greenspan, a pioneering federal researcher in infant mental health. "The important issue is how well the parents can orchestrate an environment for the emotional well-being of their baby.

"There is no evidence that having more than one adult care for the baby is harmful as long as they all love the child and don't compete. But it's very very difficult to give a formula for what works. It depends on many things, including the parent, the child, the circumstances and quality of the substitute care."

These observations echo the conclusion of an extensive 1982 National Academy of Sciences study of the effects of parental employment on children which found:

"The phenomenon itself is far too complex to identify any simple relationship between parental employment and effects on children. Work, by itself, is not a uniform condition experienced in the same way by all adults who are themselves parents. Parents are not the same; nor are their children; nor are the communities in which they live, the schools they attend, their neighbors and friends.

"In effect, if we have any message to communicate after the extensive efforts we have made, it would be to tell parents, teachers and professionals: 'Don't ask if working parents are good or bad for kids, because the answer is 'it depends.' "

Studies like this one have become increasingly common over the past decade as more and more mothers have flocked to the work force. Current research often focuses on infants, because they are being placed in substitute care in record numbers.

"Infant day care is the fastest growing type of supplemental care in our nation, with infants as young as 3 weeks being placed into out-of-home care facilities," report Thomas Gamble and Edward Zigler of Yale University's Bush Center in Child Development in a report on "the effects of infant day care." While studies of the effects of such care present "mixed findings," the positive or negative effects of infant day care are related to "the degree of stress already present in the home environment."

In an unstressed family, "short-term separation will not seriously affect quality of attachment," they write. "On the other hand, in the context of an already stressful home environment, such separation might be an added stress on the infant, acting to imbalance the attachment relationship."

The baby's sex may play a significant role in his or her reaction to substitute care, Gamble and Zigler note. They cite several studies indicating that "boys were more vulnerable to maternal employment (and father absence) than were girls."

Among the findings they cite:

*"Middle-class sons of employed mothers show lower academic performance in grade school and sometimes lower IQs" than sons of non-employed mothers.

*There is "a general tendency for boys to be more vulnerable to the ill effects of family stress . . . Family discord and 'bond disruptions' including divorce were more strongly associated with antisocial disorders in boys."

These gender differences may be a result of biological makeup and socialization practices that lead boys to respond to environmental changes by "accommodation" -- a process of altering or abandoning, perhaps unnecessarily, ongoing personality development and thought processes, they note. "Females, on the other hand, will tend to assimilate" -- a process of incorporating changes while maintaining the existing personality and thought development.

While more studies are needed to uncover the effects of substitute care on infants, Gamble and Zigler conclude that "blanket statements about the benign effects of infant day care on social competence, especially in males, may be premature."

Concern about possible ill effects of such care combined with "difficulties in providing good quality infant day care" led the Bush Center's Advisory Committee on Infant Care Leave to recommend that mothers take at least six months of maternity leave and that "alternatives to infant day care should be available to those working couples who would prefer to be with their babies during the first months of life."

Despite the difficulties in combining work and parenthood, "there are ways -- if you are conscientious, knowledgable and careful -- that you can be a working parent," says the University of Virginia's Sandra Scarr, who has spent seven years studying the effects of day care and 20 years of research in child development and the factors that determine intelligence and personality. "Research on children and child care shows us that what is important to the child is good quality care which has characteristics we can identify.

"A child's relationships can be with more than one person. We've emphasized too much children's exclusive relationship with the mother to the exclusion of what's really important -- the quality of care."

The problem with most past studies of day care is that they "look for what's wrong with the arrangement and what children are missing," says Scarr, who has four children ranging in age from 11 to 22 and who has worked full-time since her 22-year-old was 3. "Now we're looking at what's right."

Some studies show that "children with more than one attachment are better off," she says. Also, children in good day care may be more independent and score higher academically.

Scarr discovered the academic advantage of good day care when she was asked to set up a child development project for the government of Bermuda in 1977. When she tested the children, she discovered two startling things:

*About 60 percent of the children scored higher than children the same age in the United States.

*Seventy-five percent of the children were in non-maternal care by the time they were 1 year old, and 95 percent were in non-maternal care by age 3. Most received good quality care in family day care homes and for-profit day care centers.

"By the time the Bermudan children are in sixth grade, they score two years ahead of American children on the California Achievement Tests," she says. "It was an eye-opening experience for us and for them."

What many of those who crusade against day care fail to acknowledge, she says, is that full-time mothering isn't all cheery outings and cookie baking. "It's an unpopular view, but it's true that a lot of parents are not very good with young children and babies. There are a lot of incompetent, upset and depressed mothers taking care of kids who may take their boredom and frustration out on the children."

The answer isn't day care, but teaching parents how to rear their babies, argues Burton White, director of the Center for Parent Education in Newton, Mass. A trained engineer who decided that "people were more important than machines" and went on to study philosophy and educational psychiatry, White says, "everything I've learned in 29 years says it better be the parents or grandparents rearing a child , because nobody gets as excited at the child's discoveries as those six people.

"Also, the reality is that substitute care system in this country is a disaster -- the pay is low, the ratio of children to adults is too high, it raises the likelihood of infectious disease . . . self-evaluation is the licensing procedure in most states."

Good infant day care would cost so much that it would be prohibitive for most parents, contends White, who has been consulting with the Missouri Department of Elementary and Secondary Education on a "New Parents as Teacher Project" that teaches parents how to observe, stimulate and oversee the development of their babies. The results of studies in four Missouri school districts show that by age 3, toddlers whose parents received the training showed mental and linguistic growth far exceeding that of other children.

Couples who think they can't afford to have one parent stay home with a child "should think again," White asserts. "Day care is not in the best interests of babies, and I question whether it's in the best interests of mothers. I'm saddened by the thought that many adults are missing some of life's sweetest pleasures, those that parents receive when they spend time with their own babies."

Today's employed mothers may actually spend as much time with their babies as full-time mothers used to spend with their children, says the University of Michigan's Lois Hoffman. With changes such as no-iron fabrics, quick-cooking foods and smaller family size, "it's possible it is today's full-time homemaker mother who is different," she says. "Employed mothers cut back on their own leisure time and sleep in order to give more time to their children."

One reason for the great disagreement on this subject is that "advice to mothers has always been influenced by social, economic, political and ideological factors," writes Beverly Birns, psychology professor and director of Women's Studies at the State University of New York at Stony Brook, in a working paper on "The Mother-Infant Tie."

The current belief that "mothers construct their children as automobile workers build cars and, further, that the critical period in this construction is infancy" is "science fiction," she says. It is based in part on Freud's theory that adult neurosis is rooted in early infantile experience, and on subsequent interpretations that concluded, in effect, that problems with a child are the result of "a bad mother."

New evidence counters this Victorian view of child-rearing and suggests, she writes, that "factors other than mothering are significant in development and that experience during infancy may not be as important as commonly believed . . . Current advice to mothers may be burdensome to women and not in the best interest of the child."

Some parents "tired of all the contradictory advice are turning a deaf ear to the experts and tuning into their own feelings," writes Kaye Lowman in "Of Cradles & Careers." "What many of these parents are deciding is that finding an alternative to leaving the baby 40 hours a week is a top priority." The result is a movement toward a reduced work week, which, she says, "is changing the landscape of the American workplace almost as profoundly as the Industrial Revolution changed it a century ago."

One thing virtually all the experts agree on is that the current state of day care is -- as Brazelton puts it -- "grossly inadequate." Numerous experts and organizations -- ranging from the American Academy of Pediatrics to the Association of Junior Leagues -- have banded together to form the Ad Hoc Day Care Coalition, which issued a report this year calling for "private or public resources to supplement the cost to the consumer."

"There's no reason why the United States shouldn't have the best day care in the world," says Spock. "Parents must get more politically active in a country where people take care of their own children quite well, but are generally indifferent, neglectful and insensitive to the needs of children as a group."

Some people are still unconvinced that the society should step in to address these needs, says Brazelton, recalling the statement a member of Congress made to him recently when he was in Washington to testify for the Parental Leave bill: "Don't you think, Doctor, that it's not a public problem when a women has a baby? That it's her problem?" Brazelton replied: "I don't think having a baby is a problem. I think it's an opportunity, a very exciting opportunity for a whole revitalizaion, not just of the person, but of the family. That's what we're talking about when we talk about something like maternity or paternity leave.

"We're having the chance, in a society where the family is breaking down so rapidy that 58 percent of our children will have a single-parent family for a major part of their lives, to offer the families a chance to cement themselves around new babies.

"What could be more important?"