Fathers are taking an increasingly active part in family life, evident virtually everywhere one looks -- in supermarkets, carpools, doctors' waiting rooms and fast-food restaurants, on jogging trails, even in the workplace.

"I think there's always been a tremendous yearning in men to have more connection with their children," says Samuel Osherson, "and this is being tapped now. There's very definitely a trend for fathers to become more involved. It's not a tidal wave, but it is a trend."

Nowhere is this more apparent, says psychotherapist and Harvard psychologist Osherson, than in the evolving relationship between fathers and sons. "An enormous number of men these days feel that they lack something from their fathers," says Osherson, 40, "and they want to have a different relationship with their sons."

The father-son relationship went vasically unchanged for hundreds of generations. The seeds of change were planted, suggests Osherson, at the end of World War II, at the time of the suburbanization of America.

"Many of our fathers came back from the war, were told that they had fought the good fight and that they had fought the good fight and that they should enjoy the fruits of victory -- a house in the suburbs and a successful career: These guys got out of the war, started working hard, bought houses in the suburbs and suddenly they started spending all day away from their families."

They would rise early, often before the rest of the family, head off to work "with a heavy heart" and come home at early or mid-evening. Suburbanization," says Osherson, "created a generation of men who felt exiled."

Fathers of that and countless generations before, says historian-sociologist Prof. Tamara Harevan, were acting out a different, "more traditional script of what a 'normal' life meant: marry early, have more children, closer together, go off to work and leave the wife at home as homemaker."

The reality, social and behavioral scientists agree, seems to be that the fathers performed such a role -- but at enormous cost.

"I know that my father, like so many other fathers," says Osherson, "felt a lot of anger, depression and pain behind that strong -- man image. They felt they were living up to it, but they also felt this yearning to be home with the family."

Meanwhile, sons felt deserted by their fathers. Distant from them. Today, that seems to be changing. "There appears to be an appreciation on the part of young men for what their fathers are doing," says Purdue sociologist and educator Robert Lewis. "For the father's part, they seem to be reaching out, trying to maintain continuity between the generations, keeping the channels of communication open between themselves and their children."

Two significant factors behind this change are the remarkable increase in the number of two -- career families and the women's movement. Mothers haven't the time to handle careers and all the homemaking chores and fathers are aware of -- and may welcome -- the need for their added involvement in the child -- rearing process.

Historically, Harevan points out, the bonds between mother and child were stronger and "the father may havae felt like an outsider and weekend guest," another possible explanation why so many fathers today are moving to share responsibilities in housekeeping and child-care duties.

That doesn't mean there aren't concomitant problems: The men want to be home and fulfill their role as fathers, but in moving into the family, they're entering what formerly had been a feminine world. "Many men," explains Osherson, "feel a lingerlingering sense of 'Am I losing my masculine identity if I partake of this too much?'

"Despite this conflict, you can feel masculine, go to work, and also go home and take care of the kids. I find, sometimes myself, that I yearn to be home with my son, Toby, when I am at work, and when I'm home with him I sometimes think about how I should be at work."

The importance of fathers in their sons' -- and daughters' -- upbringing, says Osherson, "cannot be overestimated. They can communicate to the child, even before the child has separated mother and father, that father is dependable.

"They can communicatde to children that there is a world beyond mother that is exciting, important and worth letting go of mother for. The father says there's a whole world beyond mother and it's worth turning toward me."

Beyond a child's feeling of mourning and loss in separating from the mother, the father can help them feel a positive sense of optimism and excitement. "That," notes Osherson, "is what our fathers didn't do a lot of for us."

Three likely explanations why not: They didn't recognize the importance of their role in their children's upbringing; the pressures of society at large, and because they were trying to meet the expectations passed on to them by their fathers. "What it adds up to," Osherson says, "is a social tragedy."

Harevan, history professor at Clark University, research associate at Harvard's Center for Population Studies and editor of the Journal of Family History, sees a number of reasons today's fathers are taking a different tack in their family involvement: Men are marrying later and becoming fathers at a later age, finishing their educations and establishing their careers before marrying and becoming parents, thus "bringing a new maturity to their parenthood."

That couples often cohabit for extended periods before marrying means, suggests Harevan, that "If they do marry and have children, they are making a deeper commitment to being involved in the child-rearing process. They have negotiated their own way, in how they are having children and how involved they will be with their children."

Dr. Graham Spanier, Professor of sociology and psychiatry at the State University of New York at Stony Brook, notes that, while the children may come later, fathers are becoming involved with them at the earliest possible time: "Even before childbirth, fathers are participating in childbirth education classes, and their direct involvement most often starts right in the delivery room."

In contrast, a generation ago almost no men attended the births of their children. In 1973, about 40 percent of fathers were in the delivery room. Ten years later that figure was up to 80 percent. Current estimates are that more than 90 percent of all deliveries are witnessed by husbands.

Osherson remembers his father telling him of the day Osherson was born: " 'I was in the Army and worked all day long. I didn't even think of going to the hospital.' "

Though men are becoming fathers at a later age -- generally in their late twenties or early thirties today, as opposed to early to mid-twenties a generation ago -- there is less infant mortality and the fathers are living longer. Consequently, says Spanier, "Today's child, today's son, is more likely to grow up at a time in his father's life that is different from the boy who grew up in his father's life in the 1950s.

Also, with fewer children per family, parents are able to spend more time with each child than, perhaps, their fathers were able to spend with them.

Says Spanier, "We now have lots and lots of men who really are in the first generation of men trying to engage in a significant way in parenting and child-care responsibility. Their children are going to be the first full generation of people that have been widely exposed to this."

Osherson agrees, seeing in the evolving developments, "a very special opportunity, a great social experiment in some ways -- women working and men more involved in the family. We don't know the results."

Another area of interst in involved parents and social scientists involves the mother's reactions to the father's increased role in childrearing. Communication between husband and wife, stresses Osherson, "is very important, to help the wife not feel threatened, being aware of each other's irrational fears. Parenting is a very lonely activity for each parent."

Wives and mothers have known all along that they've had their hands in the middle of something very important -- in terms of rearing the children -- and when the husband and father comes along and says he wants to participate, the mother knows it means giving up power and control in a domain of life that, at some levels, is far more important than work. "If both parents don't feel comfortable with the father taking more part in nurturing and family," says Osherson, "then they shouldn't feel coerced by our social expectations into doing it."

Spanier says the change in father-son relationships over the last generation isn't as dramatic as some would make it. "A number of people are saying now that it's almost miraculous. Well, there is a little bit of truth in the statement that fathers of a generation ago have gotten a bit of a bum rap.

"They probably never were quite as distant in their relationships with their sons as we now think. You know, many adult children today have very fond recollections of how close they were to their fathers."

And, says Osherson, watching our fathers with our sons can provide meaningful insights. "Watching my father with my son made me realize my father is a very nurturing man. I see sides of my father that I never saw as a child."

If the father is more involved with his son, if the son is more confident in his father's presence and learns through and with his father that it's safe to feel loved, that, says Osherson, "is very important and should make a difference in that son's fathering abilities.

"If all works out well, the son will have real, vital memories of his father as present and nurturing to draw on, and those will be guides for him in taking care of his children."