The old woman on the porch with me that warm summer night in Glasgow, Ky., was my wife's grandmother, Stella. My first visit and we sat stiffly on the glider couch watching the traffic come and go at the quick store across Bunch Avenue, which years before had been aptly named Back Street.

Stella was 75 years old, small and sturdy, still curing her own ham and bacon in the smokehouse by the garden. Her skin was clear and moist and she looked less than retirement age in her wig of black ringlets, a rare vanity. Mostly, she told me stories of growing up on the farm along the Cumberland River near Burkesville, Ky., then moving to Glasgow for excitement and work in 1924 -- stories inevitably shadowed with race in the South of those days.

She recalled that a white woman married a black man in this neighborhood decades ago and that they returned home from the city only rarely, arriving and retreating at night. Otherwise, there might have been trouble.

Stella was too polite to use the word nigger in my company, though it was a chore for her. She told my wife that except for that change of habit, she could be herself and treat me like anyone else.

"When will you have children?" she finally asked.

"Someday," I answered absently; we had just married.

Two years later, Stella was dead of a heart ailment and someday was nearly upon us. Her granddaughter and my wife, with her honey-colored skin and her nose that is not European, her rising cheekbones, brown eyes and electrified hair, was pregnant with our son. And I, with my pug nose, sea blue eyes and pale Irish skin, had gotten her that way with little reflection. All of a sudden, that made me nervous.

"What about the children?"

The answer was once so simple in Glasgow or Dayton, Salt Lake City or Washington. When whites married blacks, which was infrequently, the whites melted into a separate black world. Ostracized by their race and bonded to blacks by the force of segregation, they lived as immigrants to a foreign land. Their children, regardless of shade, became black. No in between. Black is night, snow is white.

"What about the children?"

A common-sense, well- meaning question, perhaps, but one that cuts to the heart of the great white fear, the day when black and white cannot be discerned, when noses and foreheads and lips become, like religions and nationalities, cocktail conversation. The question is white confession: "Please do not bear me a grandchild who will be treated the way I have treated black people all my life."

It is a circular anxiety, the bemoaning of racism out of the fear that sustains it. But it is not complete paranoia. I discovered in conversation with black and white interracial families from Southeast Washington to Bowie to Sterling to Great Falls, Md., that their children face anguish on the playground and in the psyche. And while many of the new generation of interracial parents are raising their children as neither black nor white, it may be best, some psychologists suggest, if these children think of themselves as black. That simplifies the vital question: Who am I?

"I don't understand why my mommy married my daddy when my daddy's black," said 5-year-old Derrick Thompson of Reston. "I don't understand why white people marry brown people . . . Someone in my class said white people can't marry brown people. I said they could if they wanted. So he doesn't understand. I wish I was white. I don't know why I wish that, but I wish I was white."

That frightens me for my son, though I also found much to feel good about. Most black and white mixed couples I met believe their children have had few problems tied to race; the best numbers show that interracial marriages in America have tripled in the last 20 years, and the Gallup Poll shows that public approval of interracial marriage increased from 4 percent in 1958 to 36 percent in 1978--a shift in attitude nearly unprecedented in polling history, Alec Gallup said.

Such change is relative, though, and mixed-race children still are trapped in the surrealistic vision of standing at a doorway to two rooms, looking into each with fear of entering either.

"When I was about 11, I used to sit down and try to feel the part of my blood pumping through my veins that is white and then the part of my blood that is black," recalled a 21-year-old Washington woman whose father is white and whose mother is black. "That's when I realized how crazy that was."

It still is. At least 28 million white Americans -- whether they know it or admit it -- have black ancestry, sociologist Robert P. Stuckert has estimated. And among the 26 million black Americans, it is commonly estimated that about three- quarters have white ancestors. The slave master's power made mixed-race children common.

That may help explain why the Gallup Poll has shown over the years that more than twice as many non-whites as whites approve of interracial marriage. And why not a single black partner I met said their parents had strongly resisted their marriage to a white.

Which is, I believe, what Stella tried to tell me that night in Glasgow, when she said her father had been raised on the Burkesville farm by its white owner, a bachelor. When he died, Stella's father inherited the farm --a long leg up in that world.

Then with a whisper and a laugh, Stella confided that her father had straight black hair and almost white skin. She always wondered if he wasn't really that white farmer's son by some private liaison. It didn't matter to her, of course. Just a curiosity, a tweak at the mythology of race from the glider couch on Bunch Avenue.

"People are people," Stella said, and I believe she believed that, though it is untrue. We are people always peering into what social philosopher Charles Cooley called the "looking-glass self," people always becoming and battling what others would have us be. For my son and others like him, the glass that creates is an image of us all.

I did not marry to make a point. I married because I fell in love and I fell in love because my wife and I shared a way of seeing the world as an inhospitable place where optimism is not only a cheerful trait but a personal strategy, a world where expectations and accomplishments may diverge through no fault of our own, a world where we manipulate status and acquisition, not the reverse. We shared these values because our families, white and black working class, shared them before us.

Like anyone, blacks and whites marry because they are more alike than different. And what the couples I met shared was a quiet defiance of authority and a drive to succeed in the traditional, middle-class American way -- values they believe will temper the impact of racism on their children. Take these couples:

* Bob Raffety, 34, and Linda, 35, of suburban Upper Marlboro. He is a District police detective, an Irish kid from South Chicago who quit high school and joined the Navy. Today, he has finished high school and nearly completed college, after which he plans to go to law school at night. Linda's father was a truck driver who made good Teamster wages. Her brother is a college dean; her sister holds a masters degree and is married to a doctor.

"Marrying Bob is the dream I had," Linda said, "a little house with the white picket fence."

* Marc Hunter, 38, and Diane, 35, of suburban Maryland met while teaching in Harlem in 1970. Marc grew up in South Bronx, but his family was from Jamaica, where his father had been a schoolmaster. Marc is a management consultant finishing his doctorate at Catholic University. Diane grew up in Great Neck, N.Y., the daughter of wealthy Jewish parents.

"I want our kids to grow up appreciating the finer things in life -- money, good education, music, gymnastics," Marc said. "We want them to get an upper-middle-class culincreasture, not the street savvy of black culture."

* Skip Gump, 46, and Janice, 45, live in a large Great Falls, Md., home that Janice said they cannot really afford. But it is what Skip, the son of a high school principal from West Virginia, always wanted. They met while working at a community mental health center in Philadelphia; both hold doctorates in psychology. Janice's father was the first black vice president of Anheuser-Busch Companies, Inc.

"I wanted my son to have the advantages of thinking he can do whatever he wants to do," said Janice. "I want him to have ideas that in this culture have been largely associated with white men . . . confidence, control, self-esteem."

The thread is obvious. And whether it is because the parents of mixed-race children powerfully motivate them or because the children are driven by their own unique racial status, Harvard University psychiatrist Alvin F. Poussaint, co-author of the book Black Child Care, said many of the mixed-race students he has studied are highly motivated to succeed.

It is often this continuity of values that shatters not so much the racial but the social class bias of white parents who are almost universally shocked and angered at their child's marriage. Finding that the marriage is not a downward ride on the great escalator of social mobility paves the way for acceptance, though it often takes years.

"She was so hurt I wasn't marrying someone of her choice," said Diane Hunter of her mother, "that she could not make this engagement party, make this big wedding and bring it to the country club." Her mother finally relaxed when she found Marc wanted for Diane what she wanted for Diane. "My mom looks at us now and the way Marc is doing -- a housekeeper is good and two cars in the garage . . . They understand our caring for one another."

So it is not social rebelliousness that binds these interracial couples. Rather, it is their willingness to defy powerful social convention in their pursuit of the conventional. If this be advantage, their children will have it early on. Then they will face the world, where they will learn quickly that their lineage is a rarity that shapes friendships and futures, that white boys and white girls seldom date tan boys and tan girls, that color is not forgotten. That life in between is at once injustice and insight.

Daphne, the 12-year-old mixed race daughter of 35-year-old Gwen Thompson of Reston, was called nigger for the first time when she was about 2 years old. A white boy, perhaps 6 or 7, began running circles around her in a J.C. Penney store in Forestville, shouting, "Nigger, nigger, nigger!"

"I went to his mother and told her, and she could have cared less," said Thompson, who is white.

"Is this the first time something like this has happened?" a black clerk asked.

"Yes."

"You better get used to it."

A few years later, Daphne was playing in the back yard in their mostly black Southeast neighborhood when from inside the house, Thompson heard one of her daughter's black friends call Daphne a "half-white bitch." Thompson ran outside and brought her in the house. "My gosh, Daph," she thought. "It's going to come from both sides."

That is the great double bind for mixed-race children. Most parents face it by living in integrated neighborhoods and sending their children to integrated schools. Daphne, like other children I met, was embarrassed that her mother was white and didn't want her visiting at school when she attended the predominantly black Beers Elementary School in Southeast. But when Daphne switched to the Washington International School, with its multiracial student body, her mother's race didn't cause a whisper.

Children quickly calculate the social mathematics of being black or white, and mixed-race children in mostly black schools often want to be black and those in mostly white schools often want to be white. Listen to the conflicting messages:

"I like to be like other children usually," said Tia Hunter, 8. "And when I be like other children, I don't want to be left out . . . So when I play with the white friends, they usually don't play with the black friends . . . Sometimes I wish I could be white, sometimes black. But most of the time I wish I could be white. I like white. I like looking black. But most of my friends are white."

Though mixed-race children are sharply aware that they are different, few parents I met said their children have had grave trouble because of race. Still, mixed-race children face incidents that linger.