T WAS SOMETHING she had noticed all her life. She looked at families and saw the resemblances -- the daughter who looks like her mother, the son who looks like his father. "It always amazed me to be sitting around in a room and see people who resemble each other. But when you're an adopted child there's no one you resemble. There's sort of a missing link."

She does nt know when she first got the idea, but she knows she was not searching for a mother and father. The man and woman who adopted her 45 years ago are truly her parents, she says. They are the ones who raised her. It was that woman who taught her how to wear makeup, how to fix her hair, what to say to boys. It was that woman who taught her how to pray.

These parents, she says, who devoted their lives to her, would be devastated if they discovered what she has done. "They would wonder, I'm sure, 'what did we miss doing?.' 'What did we not do right?" So she has not told them of her search, and they will not learn of it here. She felt guilty. She felt she had betrayed her parents' trust.

And yet she began her search for the woman who gave birth to her, the woman who could complete her identity. She started more than a year and a half ago with two clues: her adoptive parents had told her the last name of her birth mother and she a birth certificate that identified the state in which she was born. She wrote the state for her true birth certificate but was turned down. Then an attorney wrote the state, explaining that "I was an adult, a mature woman, that there were no reasons for wanting to find her other than to find my medical history and my identity." The attorney obtained the true birth certificate and from it she learned her mother's full name.

Then, she spent two months in the Library of Congress. "I looked through city directories for people with that name and I was able to locate people in the town where I was born, with that name. Then, I wrote for her death certificate, for her father's death certificate. I wrote for birth certificates. I wrote to high schools in that area for information. I wrote to where her father worked, for information. Anything."

The breakthrough came with the grandfather's death certificate. On it was the name of a family member who might know what became of the natural mother. The adopted daughter wrote the family member, saying she was trying to find the woman for a family geneology. She gave this excuse to protect her natural mother. The man contacted the birth mother and she telephoned. "She sounded curious."

The woman called around Thanksgiving of 1977. "It was extremely emotional," says her daughter. "She never had any other children and her husband had died. She, of course, was an elderly woman in her 60s. My husband was observing me talking to her on the telephone for the first time and he said he had never seen all the emotions so overtake a person. Fear, joy, amazement, sorrow and guilt, all at one time. In fact, I almost collapsed."

They talked again and again on the phone, establishing a relationship and finally, they arranged to meet each other last April. "When I met her face to face, I had arranged in my mind that it would be more or less like meeting an aunt, a relative I had never met before. That's the way it really was for me. But for her, it was a tremendously emotional experience. This was a child she had never seen."

This was an illegitimate daughter conceived at a time when illegitimacy brought total disgrace to a family. She was adopted 10 days after birth. "They wouldn't let her out of the house for two or three months. She has felt that was the reason she never had any more children, that she was being punished all her life for having done this horrible thing.

"My birth mother has not told me the name of my father. She says he's dead, but this is an excuse that's sometimes given. I don't really care that much about my father and she, of course, is the only one who could tell me. Someday, she won't be around and I wonder if I'll ever know who my father was. But now that I've found her, I wonder how important it is after all. Any of it. it's terribly complicated and it's so emotional. You try to be so careful and not hurt anyone's feelings.

"Our relationship now is that we correspond regularly. I send her small gifts for Christmas and her birthday, but I really do not wish to get real close with her. She can't suddenly become my mother when I'm 45 years old and I don't want her to become my mother. I think it would be scary for her if suddenly she thought she had to become a mother.

"So many times the adopted kids and the birth parents, too, have some imaginary way of thinking of each other, and of course, it's not going to be the way they imagine. It's going to be different.... There are people who have these wonderful ideas about finding their birth parents or their birth children and having this wonderful relationship that just can't be.

"Not having any other children, she has had a tremendous possessiveness toward me. She was extremely clutchy. That frightened me.She has had to learn that I cannot call her mother, because the woman who nurtured me, who taught me right from wrong, is my true mother."

The adopted daughter began her search because she wanted to find the missing link in her identity. She wanted to know whom she resembled, from whom she had inherited talents, traits, characteristics. She wanted a genetic heritage and she wanted to thank the woman who gave her away to a better life. "Birth parents are closet people. They've borne this guilt all these years and more than likely they had no control over the situation....

"I wanted to let her know that I was alive, healthy and happy. And I wanted to ease her conscience before she would leave this earth.

"Adopted adults should not ever expect anything when they are searching for their birth parents other than an identity. The birth parents should not hope for anything if they see the children they've given up. Usually too much time has elapsed, the children are grown, they've gotten their own set of ideas and their own parents. The adoptive parents are their true and only parents.

"When I first met my birth mother she cried and cried and said do you really like me. I said, 'Oh, of course, I love you,' But it's not the same kind of love I feel for my adoptive parents. Just because a woman has a baby doesn't mean that baby's going to love her. Love comes from upbringing and care and nurturing. A mother that you can take into your confidence. All these things I had.

"I really feel her burden of guilt has eased some since I found her. She doesn't say she is disappointed, but she has said I wish you could call me mother just one time before I die.

"And I just can't do that."