FROM THE WAY she described it, the scene is not hard to visualize. It is 1945 in wartime Washington and a woman dressed in one of those widebrimmed hats and a suit with shoulder padding goes to Union Station and boards a train for New York. The woman works for the government and she is going to New York on a secret mission. She is going to give birth.

Something like this happened. It happened to a woman with an unkknown name and now her baby, all grown-up and with a child of her own, would like to find the woman who took that train. She cannot. It is not supposed to be her business. Officially, she is totally on her own.

On her own she has hit a brick wall. She has been through the birth certificates and the death certificates, combing through the paperwork left behind by a New York hospital -- Park West -- that no longer exists. She thinks she has the right name and she thinks she knows something of the circumstances: an affair between a government official and his secretary, wartime Washington, a pregnancy and that train ride to New York for the birth. It's like an old movie.

Real life, though, is harsher. In real life the person who is born cannot ever find out the name of her mother. It is, as the woman says, as if a piece of her is missing. She looks at her children and she wonders where the freckles come from, the Irish sparkle, those noses. What did their grandmother look like, and how about their grandfather?

"I want to know who I am," she says. "I want to see someone who resembles me. I want to know where my mother and father come from. I want to know why I think the way I do. I feel strongly that there is someone out there who shares similar concerns."

You can understand. You can appreciate how it must feel not to know who your mother and father are, why it is that you smile the way you do and why you walk unlike anyone else in the family. It is good to know these things. I think, for instance, that the more I know about my parents, the more I know about myself.

In most states, an adoptee has no right to know the name of his or her natural mother. This is a secret. The birth certificate is altered when a person is adopted and the original record is sealed by the court. The real mother knows the truth and, usually, the real father and sometimes even the adoptee's new parents. Only the adoptee is left out in the cold.

The reasons for this approach are obvious. Some adoptive parents fear they will lose their child once the identity of the natural mother is known. There is some sort of aprehension here that the biological bond is the strongest of all -- stronger even than a lifetime of love and caring.

As for the biological mother, she might not want her child to know her identity. Many of them give up their children because of the shame of pregnancy and some of them have the additional guilt of having in their own eyes, adbandoned their child. The last thing they want to have to account for something done years before. And, of course, secrecy is designed to assure the adoptee's parents that the natural ones won't suddenly materialize to reclaim their child.

But a recent study in Britain shows that these fears are unfounded. The Children's Act of 1975 gave persons over the age of 18 the right to find out the identities of their natural mothers. The first surprise is that very few of them chose to do so -- something like only 1 to 2 percent. Hardly a mass movement.

The study also indicated that the dire predictions of confrontations between the adoptees and their natural parents were unfounded. The why-did-you-abadon me? scenes that had been predicted were very rare. In fact, the mothers found their children understanding. They seemed to have a nice chat, a spot of tea and then they went home -- toodaloo.

This, of course, is what the adoptees have been arguing for years. They have been saying, as has the woman who was born in New York of mother unknown, that they have no desire to confront, no wish to leave home, no urge to trade in their adoptive parents for their natural ones, only a very understandable desire to find out where they come from -- to connect themselves to the whole of humanity. This the law says they cannot do.

The reason always given is that this is best for the child. Maybe the people who believe this are sincere, but the whole arrangement is so self-serving it makes you wonder. The natural mother is protected and the adoptee's parents are protected. But the one person who is forgotten in all this is the adoptee. In this case, she is a 35-year-old woman who would very much like to meet a woman who went to New York to give birth to a child. She has a question for her that the law ought to allow her to ask:

Where do those freckles come from?