Ihave a friend who's a social worker. Her clients include a group of women who've given up a child for adoption. Their ages range widely, and the moment of surrender may have been long ago or last year. They form a birth mothers' support group.

My friend says their meetings are suffused with sorrow, sometimes bitterness. They describe their lost children and the new parents as ambling through life happily, selfishly, with never a thought for the origins left behind. As an adoptive mother, I find that picture distorted.

I think of the biological father rarely, envisioning him as the dashing young fellow he must have been at the time he sired our daughter. But scarcely a day goes by when the birth mother is not in my thoughts, growing older as I do.

She's been with me from the start. When Gwyned was placed with us on probation, there was always the threat that the birth mother might change her mind and snatch our baby back. She loomed as a fearsome adversary. I pictured her wild-eyed, manic, appearing in the courtroom a moment before the final decree, shouting, "She's mine, and her name is Monica!" Our papers were approved, however, without incident.

Those papers contain my signature and my husband's. The birth parents' signatures were folded under so that we never learned their names. The papers are dated Dec. 30, 1953, and are locked away in a Maryland court house, apparently inviolate. We received a "birth certificate" proclaiming that Gwyned was born to me and my husband on May 8, 1953, in Garfield Memorial Hospital, Washington, D.C.

What is a birthday like for an adopted daughter who's 1 or 4 or 10 or 16 or all the years between and after? Just like birthdays for other children -- parties, presents, friends and family gathered to celebrate. But for me there was always a special poignancy when lighting the candles on the cake. I, the mother in residence, would think of that first mother, wondering where she was, knowing she was remembering the day. I wanted to call out to her and say, "Look how delightful Gwyned is! Thank you." My hands always shook as I carried the cake to the table, trying not to quaver as I started singing "Happy Birthday."

Gwyned didn't seem to care. She grew up in a neighborhood and attended a school where there were several adopted children. No big deal, she said. In fact, she implied that there was a special cachet to being "selected." Though she knew better, I think she fantasized about our walking down an aisle lined with bassinets until we came to her and said, "That's the one!"

When Gwyned acquired a figure, it turned out to be more svelte than the figures in my family; I imagined the birth mother trim in bikinis, mini skirts and other fashions I avoided. Gwyned took to singing in choruses, acting in plays; the birth mother became the repository of performing talents I'd never possessed. Gwyned liked skiing and running and in college elected "self defense" in gym; the birth mother assumed the dimensions of a sportswoman, perhaps Olympics material.

With the approach of Gwyned's wedding, I grew restless, then frantic. Ought we to try to contact that birth mother, to assure her everything had turned out well, possibly to invite her to the marriage? I struggled with these questions through sleepless nights and finally consulted a psychiatrist. He offered a common-sense suggestion I wish I'd thought of in my anxiety: "Why don't you ask Gwyned?" I did. She said she'd just as soon leave things as they were. She spoke as though that issue was closed. But later in life she changed her mind. After giving birth to her own children, she began to wonder about physical traits and medical histories.

At the same time, large-scale changes were in motion. Mothers were locating long-lost children; adult adoptees were searching for parents, combing registers, placing ads; associations were established to facilitate these investigations and, it was hoped, ultimate reunions. Some agencies and some states offered help to the searchers. Others clung to the conditions in force at the time of adoption -- usually an unbreachable barrier between birth parents and adoptive parents.

"Can't I get the name of at least one of my parents?" Gwyned asked. "With a name, I could search." She presented herself at the adoption agency; they declined to reveal that information. She petitioned the court and had a hearing before the judge; he said he did not want "to disturb the birth mother." In the hope that our support might be useful, my husband and I wrote to both agency and judge, to no avail.

It's difficult to sort out the rights and wrongs in a case like this. Gwyned feels compelled to close a loop that's been open all her life. She gets encouragement from support groups but also pain, since they usually include happy birth mothers and adult adoptees who have found each other. My heart aches as I observe her thus far futile efforts to pinpoint anyone who can help her, any clue that might lead to success. Sometimes I feel guilty for having failed, in the initial wonder of acquiring a marvelous child, to anticipate that the secrecy then imposed might one day frustrate us all.

Yet we can understand the adamance of the adoption agency and the court. They are simply adhering to the rules in force nearly four decades ago when the decree became final. They were parties to a contract and are loath to break it. Perhaps they may even feel they are sparing us grief. Indeed, the birth mother, if located, might not wish to be disturbed, might reject Gwyned. Or she could prove to be a disappointment.

I doubt it, though. She's been in my mind and my mind's eye for 37 years, and I'm convinced she's a sad but lovely lady. Whatever her name, and whether or not we ever find her, she, Gwyned and I are the points of a triangle that will endure all our lives.

Florence Trefethen is executive editor for books published by the Council on East Asian Studies at Harvard University.